How and why did baptism become linked to Apostle's Creed "forgiveness of sins" in the 381 Nicene-Constantinopolitan Creed?

Question

The common interpretation of

"we acknowledge one baptism for the remission of sins"

in the 381 Nicene-Constantinopolitan Creed was baptismal regeneration which makes many Baptists uncomfortable, although recent Baptist scholars still advocate that Baptists confess it (see how Gavin Ortlund argued for a Baptist interpretation, see also CBR article Baptists and the Baptism Clause).

My question has to do with the origin of what looks like an expansion from the clause in the Apostle's Creed that merely states

"I believe in ... the forgiveness of sins, ...".

How did baptism become linked to that clause in the first place? What debate / heresy precipitated this? Is "one" the keyword here (thus anticipating the Anabaptist controversy centuries later)? Why not leave it simply as "forgiveness of sins"? Who were the church fathers / theologians advocating for the expansion? Was it a deliberate expansion from the Apostle's creed, or was it added to the 325 Nicene Creed independent of it?

Did the original meaning of that clause really have to do with "baptismal regeneration" or were the framers thinking of something else, such as emphasizing the word "for" (see Gavin Ortlund's video for the many nuances and the associated Bible verses for each) ?

Answer 1

I really am no expert on the creeds and history around them. However the question is interesting and what I could dig up seems to be all around Cannon 7 of the revision (assuming the 381 Creed was indeed a revision of the first council in 325).

The Canon has a few short and longer versions but they all seem to indicate the same intent.

CANON VII Those who from heresy turn to orthodoxy, and to the portion of those who are being saved, we receive according to the following method and custom: Arians, and Macedonians, and Sabbatians, and Novatians, who call themselves Cathari or Aristeri, and Quarto-decimans or Tetradites, and Apollinarians, we receive, upon their giving a written renunciation [of their errors] and anathematize every heresy which is not in accordance with the Holy, Catholic, and Apostolic Church of God. Thereupon, they are first sealed or anointed with the holy oil upon the forehead, eyes, nostrils, mouth, and ears; and when we seal them, we say, “The Seal of the gift of the Holy Ghost.” But Eunomians, who are baptized with only one immersion, and Montanists, who are here called Phrygians, and Sabellians, who teach the identity of Father and Son, and do sundry other mischievous things, and [the partisans of] all other heresies—for there are many such here, particularly among those who come from the country of the Galatians:—all these, when they desire to turn to orthodoxy, we receive as heathen. On the first day we make them Christians; on the second, catechumens; on the third, we exorcise them by breathing thrice in their face and ears; and thus we instruct them and oblige them to spend some time in the Church, and to hear the Scriptures; and then we baptize them. (Nicene and Post-Nicene Fathers 2.14: The Seven Ecumenical Councils Schaff, Philip; Wace, Henry)

From what appears from this canon and what seems to make sense in it in the context of various groups claiming to be Christian, but having different doctrines or a baptism not the same as that which was practiced by the majority (such as a single immersion) or possibly not even undergoing baptism at all, they wanted to ensure a standard that would be used in the incorporation / identification with the then Catholic church. By doing so, those who would refuse the baptism after these rules of entry, could be more formally considered as outside their church.

Answer 2

Here is one path to the change/addition.

The Nicene Creed came about in 325. (for our salvation)

The Constantinople Creed (ibid) came about in 381. (one baptism for the remission of sins)

The Apostles Creed is first mentioned about 390. (the forgiveness of sins)

In 251, the baptism controversy between Cyprian and Pope Stephen of Rome raged. Cyprian et al argued strongly that only in the Church would someone find the one baptism. This is in contrast to those who thought baptism by heretics was equivalent. Here are some excerpts from Cyprian's letter with various bishops in attendance (emphasis mine).

Behold to what kind of things the Church is compelled4681 to consent, and is constrained without baptism, without pardon of sins, to hold communion. And this thing, brethren, we ought to flee from and avoid, and to separate ourselves from so great a wickedness, and to hold one baptism, which is granted by the Lord to the Church alone.

Although we know that all the Scriptures give witness concerning the saving baptism, still we ought to declare our faith, that heretics and schismatics who come to the Church, and appear to have been falsely baptized, ought to be baptized in the everlasting fountain

Unless therefore they receive saving baptism in the Catholic Church, which is one, they cannot be saved, but will be condemned with the carnal in the judgment of the Lord Christ.

If to heretics in baptism their sins are remitted, they come to the Church without reason. For since, in the day of judgment, they are sins which are punished, there is nothing which the heretics can fear from Christ’s judgment, if they have already obtained remission of their sins.

so that they who have not been baptized in the Church of our Lord Jesus Christ, and have not obtained by this means remissions of their sins, when the day of judgment shall come, should impute to us that through us they were not baptized, and did not obtain the indulgence of divine grace.

My opinion is this, that heretics coming to the Church should be baptized, for the reason that among sinners without they can obtain no remission of sins.

We, as far as in us lies, do not hold communion with heretics, unless they have been baptized in the Church, and have received remission of their sins.

Basically, Cyprian was asserting that there is one baptism and pardon of sin found nowhere else. It simply took more time for all to believe it. They defined and tied "remission of sin" with the singular Trinitarian baptism found in the Church/church.