Regardless of how the terminolgy of the Trinity was adopted, christians always believed it because it was taught by the Apostles.
Not all Christians believed it though. There were always heretical versions of Christianity such as Arianism,and the doctrines needed to be developed by theologians and defined by councils approved by the popes,or by letters of the popes themselves,in response to heretical opinions,so that the true doctrines would be clear. The belief in the Trinity needed to be developed for the very reason that it was threatened by Arian opinions.
We know this from the writings of Ignatius, Justin, Irenaeus, etc. Papal infallibility and indulgences were not taught by the Apostles in any terms but rather the doctrines were “developed” (created) much later.
Paul remitted the punishment for sins of others in place of Christ. If Paul could do it even though he was not the head of the whole Church,then certainly the successor to Peter can do it.
Not quite. You are omitting the controversial part of the doctrine…
CCC 1471
"An indulgence is a remission before God of the temporal punishment due to sins whose guilt has already been forgiven, which the faithful Christian who is duly disposed gains under certain prescribed conditions** through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints**.
When you read “actions of the Church” you can substitute “Church” for “pope” because he is the only one in the Church with the authority to create and distribute indulgences.
The pope isn’t the only one who can give indulgences – any priest can. An indulgence is simply the removing of punishment for sins which have been confessed and forgiven.
And it is absolutely foreign to the Faith of the Fathers that the pope can “dispense and apply” the merits of others to satisfy for punishment for sin.
St. Paul used his own merits to remit the punishment for sins of others,so why should not the pope be able to dispense and apply the merits of the saints to do the same?
“Now I rejoice in my sufferings for your sake, and in my flesh I complete what is lacking in Christ’s afflictions for the sake of his body, that is, the church” (Col. 1:24).
Cyprian,Letter 13,
To the Clergy, Concerning Those Who are in Haste to Receive Peace. A.D. 250:
- “Since, however, you intimate that some are petulant, and eagerly urge their being received to communion, and have desired in this matter that some rule should be given by me to you, I think I have sufficiently written on this subject in the last letter that was sent to you, that they who have received a certificate froth the martyrs, and can be assisted by their help with the Lord in respect of their sins, if they begin to be oppressed with any sickness or risk; when they have made confession, and have received the imposition of hands on them by you in acknowledgment of their penitence, should be remitted to the Lord with the peace promised to them by the martyrs.”