Justification Solely by Faith...Paul's original doctrine of the new testament. Check out Augustine.
The Catholic Bishop of Hippo never believed in Sola Fide. You can’t believe certain things and also believe Sola Fide, there are incompible beliefs.
He believed baptism regenerated the believer and you needed penance (referring to confession) after you fall into sin to be saved
“In three ways are sins remitted in the Church; by baptism, by prayer, by the greater humility of penance; yet God does not remit sins except to the baptized. The very sins that he remits first, he remits only to the baptized [Sermon to Catechumens on the Creed 16 (c. A.D. 395)].”
He believed there was no salvation outside the Church:
“We believe also in the holy Church, assuredly the Catholic. For both heretics and schismatics style their congregations churches. But heretics, in holding false opinions regarding God, do injury to the faith itself; while schismatics, on the other hand, in wicked separations break off from brotherly charity, although they may believe just what we believe. As a result neither do the heretics belong to the Catholic Church, which loves God; nor do the schismatics form a part of the same, inasmuch as it loves the neighbor, and consequently readily forgives the neighbor’s sins, because it prays that forgiveness may be extended to itself by him who has reconciled us to himself, doing away with all past things, and calling us to a new life And until we reach the perfection of this new life, we cannot be without sins. Nevertheless it is a matter of consequence of what sort those sins may be [Faith and the Creed 10:21 (A.D. 393)].”
“Just as baptism is of no profit to the man who renounces the world in words and not in deeds, so it is of no profit to him who is baptized in heresy or schism; but each of them, when he amends his ways, begins to profit from what was not profitable before, but was already in him [On Baptism, Against the Donatists 4:4:6 (A.D. 400)].”