In trinitarian doctrine, what role does the Holy Ghost fill that the Father can't / doesn't?

My understanding is, that according to trinitarians:

  • The Father is a spirit
  • The Holy Ghost is a spirit
  • The Father can indwell someone
  • The Holy Ghost can indwell someone
  • The Father bears witness of the Son
  • The Holy Ghost bears witness of the Son

The Son, after his incarnation, has a body so it seems clear that he has a distinct role, and those point don't directly apply to him. But it's unclear what makes the Holy Ghost different enough in trinitarian doctrine to make him a distinct person / have a distinct role.

  • The Father indwells in spirit. The spirit in which he indwells is the Holy Spirit.
    – Nigel J
    Jun 24, 2020 at 8:36
  • What purpose does Eve serve that Adam doesn't ? After all, Eve means life, but, then again, both her husband and her children were (also) alive.
    – user46876
    Jun 24, 2020 at 15:20
  • Whatever the Son witnesses of, He's the faithful Witness, Rv 1:5; 3:14. He declares the Father, Jn 1:18. The Son is the Spirit, 1 Cor 15:45; 2 Cor 3:17. Christ indwells and wants to indwell more us His believers, Rm 8:10; Eph 3:17. The Bible is not Modalism, but it's not afraid of oneness; Deut 6:4; Jn 14:10-11. If your understanding of "trinitarian doctrine" = "separate persons," then that's polytheism, tritheism; not triunity. I'm curious where you got it from, sir
    – Walter S
    Jun 25, 2020 at 6:04
  • 1
    @Walter Smetana The trinity doctrine maintains 3 distinct 'persons' subsisting in the one Being of God, but that is not polytheism as the 3 are 1 God, not 3 gods. Tritheism is what pagan triads of deities have, but a triad is not a trinity. The trinity has 1 Being of God, whilst triads require 3 gods.
    – Anne
    Jun 25, 2020 at 8:20
  • 1
    @WalterSmetana I think I get the concern now and adapted the sentence which contained "separate". Distinct is fine.
    – kutschkem
    Jun 28, 2020 at 7:12

6 Answers 6


Regarding the mission (missio = a sending) of the the Divine Persons,

  1. The Father cannot be sent:
    Summa Theologica I q. 43 a. 4 co.:

    The very idea of mission means procession from another, and in God it means procession according to origin, as above expounded (a. 1). Hence, as the Father is not from another, in no way is it fitting for Him to be sent; but this can only belong to the Son and to the Holy Ghost, to Whom it belongs to be from another.
    missio in sui ratione importat processionem ab alio; et in divinis, secundum originem, ut supra dictum est. Unde, cum pater non sit ab alio, nullo modo convenit sibi mitti; sed solum filio et spiritui sancto, quibus convenit esse ab alio.

  2. The Son is sent invisibly:
    Summa Theologica I q. 43 a. 5 co.:

    The whole Trinity dwells in the mind by sanctifying grace, according to Jn. 14:23: "We will come to him, and will make Our abode with him." But that a divine person be sent to anyone by invisible grace signifies both that this person dwells in a new way within him and that He has His origin from another. Hence, since both to the Son and to the Holy Ghost it belongs to dwell in the soul by grace, and to be from another, it therefore belongs to both of them to be invisibly sent. As to the Father, though He dwells in us by grace, still it does not belong to Him to be from another, and consequently He is not sent.
    per gratiam gratum facientem tota Trinitas inhabitat mentem, secundum illud Ioan. XIV, ad eum veniemus, et mansionem apud eum faciemus. Mitti autem personam divinam ad aliquem per invisibilem gratiam, significat novum modum inhabitandi illius personae, et originem eius ab alia. Unde, cum tam filio quam spiritui sancto conveniat et inhabitare per gratiam et ab alio esse, utrique convenit invisibiliter mitti. Patri autem licet conveniat inhabitare per gratiam, non tamen sibi convenit ab alio esse; et per consequens nec mitti.

  3. Holy Ghost is sent visibly:
    Summa Theologica I q. 43 a. 7 co.:

    God provides for all things according to the nature of each thing. Now the nature of man requires that he be led to the invisible by visible things, as explained above (q. 12 a. 12). Wherefore the invisible things of God must be made manifest to man by the things that are visible. As God, therefore, in a certain way has demonstrated Himself and His eternal processions to men by visible creatures, according to certain signs; so was it fitting that the invisible missions also of the divine persons should be made manifest by some visible creatures.

    This mode of manifestation applies in different ways to the Son and to the Holy Ghost. For it belongs to the Holy Ghost, Who proceeds as Love, to be the gift of sanctification; to the Son as the principle of the Holy Ghost, it belongs to the author of this sanctification. Thus the Son has been sent visibly as the author of sanctification; the Holy Ghost as the sign of sanctification.

    Deus providet omnibus secundum uniuscuiusque modum. Est autem modus connaturalis hominis, ut per visibilia ad invisibilia manuducatur, ut ex supra dictis patet, et ideo invisibilia Dei oportuit homini per visibilia manifestari. Sicut igitur seipsum Deus, et processiones aeternas personarum, per creaturas visibiles, secundum aliqua indicia, hominibus quodammodo demonstravit; ita conveniens fuit ut etiam invisibiles missiones divinarum personarum secundum aliquas visibiles creaturas manifestarentur.

    Aliter tamen filius et spiritus sanctus. Nam spiritui sancto, inquantum procedit ut amor, competit esse sanctificationis donum, filio autem, inquantum est spiritus sancti principium, competit esse sanctificationis huius auctorem. Et ideo filius visibiliter missus est tanquam sanctificationis auctor, sed spiritus sanctus tanquam sanctificationis indicium.

  • While you are correct that the Summa does indicate that the Son is sent invisibly and the Spirit is sent visibly; these aren't exclusive. The Incarnation is the Son being sent visibly.
    – eques
    Jun 25, 2020 at 13:29

A problem when trying to grapple with questions like this is the way our word ‘persons’ is not really what the original language meaning was. But I don’t want to delve into that as you are specifically asking for any distinct roles the Holy Spirit has that the Father has not. Well, could this be a case of, not ‘cannot have’ but ‘will not have’? Further, is the query as to “what makes the Holy Ghost different enough in trinitarian doctrine to make him a separate [sic] person” back to front? If it were put the other way around, would an answer be forthcoming? Consider: “What makes the distinct role of the Holy Spirit in the Trinity sufficient to clarify his person-hood as distinct from the person-hood of the Father (and the Son)?” Yet I must stick to YOUR question, and not try to inflict my one on you! However, if you bear in mind the importance of getting the right trinitarian order established, then the answers are – although never easy – a bit easier to fathom.

There is a patristic maxim that may well apply here: opera ad extra trinitatis indivisa sunt – meaning, “The external works of the Trinity are undivided” – even if these opera are ‘appropriated’ to one or other person of the Godhead. Let me now quote an example of that point in the book below:

“The resurrection [of Christ] while chiefly attributed to the Father (Acts 2:32; 17:31; Rom. 8:11; 1 Cor. 15:15), is also seen to be an action of the Son (Jn. 2:19-21; 10:17-18). But, according to Paul, it is also ‘through the Spirit of holiness’ that Jesus ‘was declared with power to be the Son of God, by his resurrection from the dead’ (Rom. 1:4). This, coupled with the ‘faithful saying’ that Jesus was ‘vindicated by the Spirit’ (a reference to the resurrection as his ‘justification’, 1 Tim. 3:16), and Peter’s words ‘He was put to death in the body but made alive by the Spirit…’ (1 Pet. 3:18), underlines the Spirit’s role in the resurrection.” Sinclair Ferguson, The Holy Spirit, p53 (ivp 1996)

I would suggest that the above example obtains with every work of the Holy Spirit you care to mention, notwithstanding Geremia’s answer, for that deals with the manner of ‘sending’ the Spirit into the world for His mission, and is not actually dealing with the work of the Spirit. The logistics of organising a mission cannot be the same as the actual work of mission done by the one sent on it. The Father is never spoken of in scripture as “being sent”, but of sending. That, alone, signifies one predominant aspect of the Father, but the Son also sends, and “the Spirit gives life” – 2 Corinthians 3:6 – and gives to each one certain of His gifts. To ‘give’ in those senses is equal to ‘sending’ life and gifts to believers. Yet there is a clear emphasis in scripture of the extent of the three persons’ sending.

Perhaps the degree of scriptural references to the various functions and roles of the three persons in the Godhead shows both their distinctions and their oneness. There is order within the Godhead. The Son relates to the Father in a particular way, and the Holy Spirit relates to the Father and the Son in particular ways. This shows that the Son is not the Father, and the Holy Spirit is neither the Father nor the Son. Yet their oneness is indisputable, for they all have the one Being of God.

That is why ‘opera ad extra trinitatis indivisa sunt’ – “The external works of the Trinity are undivided” – applies to why the Holy Spirit does a particular work, showing him to be distinct as one of the persons of the Trinity, yet the Triune God remaining utterly one in the three persons. This is no different to how the Son does a particular work, showing him to be distinct as one of the persons of the Trinity, yet the Triune God remaining utterly one in the three persons.

  • Dear Anne, I hope you might understand my words, to either correct me, or to arrive at mutual understanding (should you care to) and further adoration and love of our Triune God. I believe I understand the good intent behind your words above, "that the Son is not the Father, and the Holy Spirit is neither the Father nor the Son." But the divine words instead read, "the Lord is the Spirit," 2 Cor 3:17. And, "a Son is given...His name will be called...Eternal Father," Isa 9:6. Among other verses. Now Paul and Isaiah don't mean Modalistically; neither do I. But Scripture's not afraid of "is."
    – Walter S
    Jun 26, 2020 at 4:14
  • What a good point, Walter! Yes, getting the balance right is tricky. I should explain that when I use the phrase, "The Son is not the Father and the Holy Spirit is neither the Father nor the Son", it is to deal with those (like the LDSs) who misunderstand the Trinity doctrine. They think it means the Son IS the Father, Jehovah, when it says no such thing. So, I hope to startle them into thinking that maybe they have misunderstood the Trinity doctrine. Yes, the scriptures boldly say "is" (as you point out) and I heartily agree with that but my emphasis here had to lie elsewhere. Appreciated.
    – Anne
    Jun 26, 2020 at 18:41
  • o no Anne. Or o yes Anne! You bring up another word. 'Jehovah,' 'He Is Who He Is,' 'I Am.' We (Christians) don't take that Name or description of God, to mean 'Father only,' do we? 'For unless you believe that I am, you will die in your sins,' Jn 8:24; 'Jehovah will go forth and fight against those nations...His feet will stand in that day on the Mount of Olives,' Zech 14:3-4. 'This Jesus...will come in the same way as you beheld Him going into heaven. Then they returned to Jerusalem from the mount called Olivet, which is near Jerusalem, a Sabbath day's journey away.' Lk 1:11-12. Thanks
    – Walter S
    Jun 27, 2020 at 1:44
  • @Walter Smetana LDS doctrine distorts the orthodoxly biblical teaching about the one Being of God so that they say the Jehovah of the OT is the Jesus of the NT, and Jehovah was birthed as a spirit baby to another god, Elohim, and his spirit wife. This firstborn (of many other spirit children) they named Jehovah, who later became the man, Jesus. As this Q is asked by an LDS, my answer has that in mind but others may not appreciate that. I won’t deviate into other peoples’ points as I’m sticking to the OP, if you don’t mind.
    – Anne
    Jun 27, 2020 at 10:11
  • @NigelJ I had in mind the Athanasian creed, but I don't know how to properly scope the question. I didn't know there was much of a difference between denominations professing "oh we all believe in a trinity" regarding what the Trinitiy IS.
    – kutschkem
    Jul 5, 2020 at 7:10

The question seems to assume a degree of distinction that does not exist. If it can be allowed that scripture draws a distinction between God and the Word of God:

and the Word was with God

and if that distinction can be allowed to be both clear and yet not representative of total ontological separation:

and the Word was God

then the same can be understood regarding the Spirit of God.

As Geremia has pointed out, both the Word (Son) of God and the Spirit of God are sent and Aquinas has correctly reasoned that, as this action requires a sending agency of greater authority and that the sender is God of whom there is no greater authority, the primary distinction in role lies just here: While both the Spirit and the Word always accomplish perfectly and completely what God intends because they are both eternally God, they nonetheless operate under the authority of the sender. This is not a distinction in 'being' but in 'function' and the purpose is that we might know God personally and intimately as Father.

The Father represents a similar distinction from God because GOD is not, by default, a Father to all (1 John 2:23). GOD works by the power of His Spirit to transform slaves of sin into children for Himself in and through His Son:

But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God. - Galatians 4:4-7

If anyone is in Christ he is a new creation. The grace of God has granted that, by an appeal of faith to the sacrifice of the Son of God for reconciliation, the Holy Spirit of God indwells the believer's heart to promote conformity to the life of the Son whom He loves and by that Spirit we cry "Abba, Father".

The new birth (John 3) is entirely Trinitarian. God becomes your Father when you accept the revelation of His Son and His Spirit inaugurates and guarantees Christ in you, the hope of glory.

No one who denies the Son has the Father. Whoever confesses the Son has the Father also. - 1 John 2:23

  • GOD is not, by default, a Father to all. Not true. Eph 4:6, Matt 23:9, Is 64:8, Mal 2:10 (One Father who created us) 2 Cor 1:3b, Is 63:16, 1 John 3:1... Examples of God who IS Father - the father IS God
    – steveowen
    Jun 28, 2020 at 23:45
  • @user48152 All of these passages are addressed to God's covenant people and the Old Testament passages are figurative in that God is their creative Father. God the Father has only one begotten (unique if it pleases you) Son and we are sons in him. Jun 29, 2020 at 11:29

Jesus clearly identified the distinct role of the Holy Spirit in John 16:

5But now I go my way to him that sent me; and none of you asketh me, Whither goest thou? 6But because I have said these things unto you, sorrow hath filled your heart. 7Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.
8And when he is come, he will reprove the world of sin, and of righteousness, and of judgment:
9Of sin, because they believe not on me;
10Of righteousness, because I go to my Father, and ye see me no more;
11Of judgment, because the prince of this world is judged.

So, it is the distinct role of the Holy Spirit to reprove the world of:

  • SIN - not transgression of the Law of Moses, but specifically unbelief that Jesus is God.

    In John 8:23-24, Jesus reproved the Jews concerning belief in him:

    23... Ye are from beneath; I am from above: ye are of this world; I am not of this world. 24I said therefore unto you, that ye shall die in your sins: for if ye believe not that I am he, ye shall die in your sins.

    When Jesus said to the Jews, "if ye believe not that I am he", it is important to understand who the "he" is referring to. It can only be a reference to Jesus' prior statement in verse 19:

    19... Ye neither know me, nor my Father: if ye had known me, ye should have known my Father also.

  • RIGHTEOUSNESS - not that which is associated with the Law of Moses, but specifically that which is by faith of Jesus Christ (Romans 3:20-22 KJV):

    20Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin. 21But now the righteousness of God without the law is manifested, being witnessed by the law and the prophets; 22Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe: for there is no difference:

  • JUDGEMENT - not judgement that is associated with evil (harm, distress, disaster, etc) that comes in this life as a consequence of transgressing the Law of Moses, but specifically that associated with the evil one, i.e. "the prince of this world". He has been judged and all those whose father he is are judged along with him (John 8:44-47 KJV):

    44Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. 45And because I tell you the truth, ye believe me not.
    46Which of you convinceth me of sin? And if I say the truth, why do ye not believe me? 47He that is of God heareth God's words: ye therefore hear them not, because ye are not of God.

The Father sent the Son, and while he walked in 1st century Palestine he reproved the Jews in regard to sin, righteousness and judgement, but when the Son returned in glory to the Father, it was given to the Holy Spirit to then reprove the world in the same regard until Jesus returns.


Limiting God

Is it hard to reduce God to a checklist

"But will God indeed dwell on the earth? Behold, heaven and the highest heaven cannot contain You, how much less this house which I have built!" 1 Kings 8:27

What God cannot do

Remember the Angel's words

"For nothing will be impossible with God.” Luke 1:37

So asking what is this that God cannot do may be a hard question.

Old Testament

In the OT the Holy Ghost is mentioned several times with characteristics and activities that may overlap with those of the Father, but it is mentioned separately in the Scriptures as an entity (similar as the Father is mentioned).

"Create in me a clean heart, O God, And renew a steadfast spirit within me. Do not cast me away from Your presence And do not take Your Holy Spirit from me." Psalm 51:10,11

New Testament

In the NT Jesus explains the role of the Holy Ghost as comforter, guide, teacher.

Jesus portrays the Father deciding and accompanying in the passing of every bird

"Are not two sparrows sold for a cent? And yet not one of them will fall to the ground apart from your Father." Matthew 10:29

A humble task for the Father.

In John 14 Jesus says

"But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you." John 14:26

So, in words of the Son, the Spirit is sent by the Father.

In John 15 Jesus addresses again the issue

"When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me" John 15:26

Since the idea of the Father sends the Spirit is repeated for the 2nd time in the same conversation, it may be an important one. I understand that the Father and the Spirit are two persons.

The Apostles say the Spirit is an intercessor, comforter and guide.

Paul in Romans 8 says

"In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words" Rom 8:26

It is given that intercedes for us upon the Father, so there are different roles again.

Then he tells us that Jesus is interceding

"who is the one who condemns? Christ Jesus is He who died, yes, rather who was raised, who is at the right hand of God, who also intercedes for us." Rom 8:34

Paul says that Jesus is the intercessor, so there are some overlapping roles not only between the Father and the Spirit, but also between the Spirit and the Son.

The mystery of the Trinity is hard to explain for us mortals, let the Spirit guide us to the truth.


If we are seeking a possible historical source that gave rise to the prominent position of the "Holy Ghost" in the Trinity dogma then I would look to the Egyptian deity Horus (aka Her, Heru, Hor, Har) who was the lastborn of the first five original gods.

The reason I point to Horus is that he is a bird:


The significance of Horus being a bird is that it means that he is mobile.

In practical terms it meant that Horus could be on hand to effect divine will in distant places. It also means that he can enter into various persons.

While the Jewish and Christian symbolism is often that of a dove, such as with Noah and Jesus' baptism, the more common Jewish and Christian symbolism for this kind of "mobility" is that of "breath" and other forms of moving air.

Now the Son of God, Jesus, is essentially God's "body" or "face" (like the Executive branch of the US government), the "breath" is the invisible but remotely and inwardly acting agent in the divine economy. So God expresses himself through the Messiah but the Messiah operates by the indwelling and outbreathed effects of the divine breath aka the PNEUMA.

This, I believe, properly explains the conception and historic rationale of the concept of the PNEUMA and "the Holy Breath" aka "Holy Spirit".

Tertullian was the first to use the word "Trinity"/"Triad". He was not referring to the Godhead being three equal divine Persons but rather he was referring to the structure of God's "economy". The "economy" was the way that God expressed himself and handled his dealings, which Tertullian conceived of as a triad. For him, God handled his dealing through a triad of which he Himself was the founding member.

  • 1
    Christian sources would be more appropriate than pagan sources when trying to explain what the question is asking: What role does the Holy Ghost fill that the Father can't? Your answer does not come close to answering this question and as such I am deleting it. You are quite free to edit you response at anytime and flag it for reopening by a moderator.
    – Ken Graham
    Jun 29, 2020 at 23:06

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