What is the doctrine of the Trinity?

Question

What is the doctrine of the Trinity as defined by Christianity?

Obviously there are three entities involved: God the Father, Christ, and the Holy Spirit, but is there more to the definition?

Answer 1

As you already understand, the doctrine of the Trinity states that there is one God, who exists in three persons. The Father, the Son, and the Holy Spirit.

From http://carm.org/trinity

The Father is not the same person as the Son; the Son is not the same person as the Holy Spirit; and the Holy Spirit is not the same person as Father. They are not three gods and not three beings. They are three distinct persons; yet, they are all the one God. Each has a will, can speak, can love, etc., and these are demonstrations of personhood. They are in absolute perfect harmony consisting of one substance. They are coeternal, coequal, and copowerful. If any one of the three were removed, there would be no God.

...

There is, though, an apparent separation of some functions among the members of the Godhead. For example, the Father chooses who will be saved (Eph. 1:4); the Son redeems them (Eph. 1:7); and the Holy Spirit seals them, (Eph. 1:13).

I'd like to expand on that, but there's not much I could expand on that hasn't already been covered in depth on this site. And while it's really not a complex doctrine, all sorts of heretical teachings come about based on a misunderstanding of it, or a rejection of it. Rather than going into any more detail here, I'd just recommend browsing the various questions tagged "Trinity" here.

Answer 2

On birth of Jesus Christ and His life, Death and Resurrection, it became essential to conceive the Doctrine of Trinity. Most obvious and direct evidence for Trinity originate from Bible depicting Jesus Christ and Holy Spirit with Nature of God. Therefore, if Father is God, Son is God and Holy Spirit is God than that’s it.

Father being God is acceptable to many which is as easy as accepting existence of God.

Jesus as God:
Instead of quoting all those verses from NT, where Jesus is depicted as same as God, here are few more events that leads us to know about this claim.

1. To quote Church historian Jaroslav Pelikan, he has pointed out that the oldest Christian sermon, the oldest account of Christian martyr, the oldest pagan report of the church, the oldest liturgical prayer, 1 Corinthians 16:22, all refer to Jesus as Lord and God.

Pelikan said, "Clearly, it was the message of what the church believed and taught that 'God' was an appropriate name for Jesus Christ." Do you see any possible way this could have developed, especially so soon, if Jesus had never made transcendent and messianic claims about himself? Not unless you're prepared to argue that the disciples completely forgot what the historical Jesus was like and that they had nothing to do with the traditions that start showing up twenty years after his death.”

.2. He was crucified precisely for this charge when He declared that He is the Son of God thus making Himself equal with God.

.3. Think of the story of Jesus walking in the water, found in Matthew 14:22-33 and Mark 6:45-52. Most English translations hide the Greek by quoting Jesus as saying, "Fear not, it is I." Actually, the Greek literally says, "Fear not, I am." Those last two words are identical to what Jesus said in John 8:58, when he took upon himself the divine name "I am," which is the way God revealed himself to Moses in the burning bush in Exodus 3:14. So Jesus is revealing himself as one who has the same divine power over nature as Yahweh, the God of the Old Testament.

.4. One of the most striking is his forgiving of sin. If you do something against me, I have the right to forgive you. However, if you do something against me and somebody else comes along and says, "I forgive you," what kind of cheek is that? The only person who can say that sort of thing is God himself, because sin, even if it is against other people, is first and foremost a defiance of God and his laws. So along comes Jesus and he says to sinners, "I forgive you." The Jews immediately recognize the blasphemy of this. They react by saying, "Who can forgive sins but God alone?" Not only did Jesus forgive sin, but he asserted that he himself was without sin. And certainly sinless-ness is an attribute of deity.

.5. The way God was going to save the world was by his Son dying. God, in his divine nature does not die. So He had to come as a human being to accomplish that task. And Jesus believed he was the one to do it. Jesus said in Mark 10:45, "I did not come to be served but to serve and give my life as a ransom in place of many." This is either the highest megalomania or it's the example of somebody who really believes, as he said, "I and the Father are one." In other words, "I have authority to speak for the Father; I have power to act for the Father; If you reject me, you've rejected the Father."

Holy spirit as God:
There are these verses and many more that depict Holy Spirit as the Person of Trinity.

1 Corinthians 2:11; 1 Corinthians 6:11; 1 Corinthians 6:19; 1 Corinthians 12:13; 2 Corinthians 3:5; 2 Corinthians 3:17-18; 2 Corinthians 13:13/14;Galatians 6:8; Ephesians 2:17-18; 1 Thessalonians 1:2-5; Hebrew 3:7-11; 2 Peter 1:21 etc.

1. 2 Cor 13:14 and Mt 28:19 both prove the personality of the Holy Spirit. In both passages, there is a "person, person, person" sequence. (Father, Son, Spirit).

2. 2 Cor 13:14 concludes with these important words: "be with you all". Three things are to be with you: "May Christ's grace be with you. May God's love be with you. May the Spirit's fellowship/sharing/companionship be with you." This exactly echoes the promise of the "comforter" in John 14:16-17, "And I [Jesus] will ask the Father, and He will give you another [Gr. allos: of the same kind as Jesus] Helper, that He [the Holy Spirit] may be with you forever; that is the Spirit of truth, whom the world cannot receive, because it does not behold Him or know Him, but you know Him because He abides with you, and will be in you." So Paul's desire in 2 Cor 13:14 for Christians to have the "fellowship of the Holy Spirit" is EXACTLY what Jesus promised in John 14:17 of the Spirit: "He abides with you, and will be in you".

3. The verse 2 Cor 13:14 says that the "person of Jesus Christ" is the source and supplier of grace, the "person of God" is the source and supplier of Love and the "person of the Holy Spirit" is the source and supplier of fellowship.

Conclusion:
Trinity is depicted in amorphous manner in OT and explicitly in NT. The reason for it being explicit in NT is when Jesus came into this world, the true nature of One Almighty God was also revealed through His message. God the father was revealed in OT. Second person was revealed by arrival of Jesus and the third person was revealed after Jesus was glorified. That is why we find most of the references to God the father in OT, God the Son in Gospels and majority of the references in explaining God the Holy spirit, after Jesus was glorified.

Answer 3

The doctrine of the Trinity is the logical construct whereby three of the most obvious but otherwise seemingly contradictory bits of Scripture are reconciled. Namely:

1. That the Creator of the Universe (God the Father), YHWH to the Jews was God

   Point one is not in dispute - the work of the Creator who proclaims himself to be God is God.

2. That Jesus, the Incarnate "son of God" was God

   Point two - that Jesus the Christ is God is the defining belief of a Christ-ian (regardless of what this site's definition may be!). That Jesus claimed to be God is pretty well established, both throughout the book of John, and in other questions on this site.

3. That there is only one God

   Point three - that there is only one God, is made throughout the Old Testament. You cannot be mono-theistic and believe in more than one God.

The basic definition of the Trinity was popularized and credalized in the Nicene Creed, in which monotheistic Christians declare belief in God the Father, God the Son, and God the Holy Spirit. Furthermore, the Nicene Creed says that God the Son is "of one Being with the Father," and that the Holy Spirit proceeds "from the Father through (or and) the Son." This is the most widely held formulation of the Trinity - and is accepted by all but the most fringe of Christians.

Reconciling that God is one, and yet exists as three distinct persons is the central "problem" of the Trinity, and most heresies about the nature of God come from over stressing either their oneness or their distinctness.

It is not tritheism (meaning that there are three Gods) nor is it one God who just appears in three different forms.

It is always contentious. and other questions show why many analogies just don't work.

That this "mystery" has no earthly equivalent is not, however, an impossible defect - for it is simply understood that "God's ways are higher than our ways, and his thoughts higher than our thoughts." In other words, there is no law that says mortals need to be able to understand God's nature, just because there is no terrestrial equivalent.