I’m sorry, but your or other’s opinion, interpretation and quotes notwithstanding, the Church has never taught OSAS. The support from Sacred Scripture has already been posted several times.
Download Romans into an MP3 player and listen to it about 50 times. Think it through ,..through faith in Christ.
OSAS, because there is nothing we can do to earn our salvation, we also can’t do anything to lose it once He gives it.
It is by faith, not by the law that we are saved because it is by His grace, not by debt.
The Christian church most certainly DID teach justification by faith. This doctrine supports the truth that we are not saved by our works but by faith in Christ. And if we are saved by faith - are justified by faith - then it is not something we can lose by our works or by our sin. Though no one may have used the terminology OSAS, it nevertheless is Scripturally true. I've already given you a link that shows ECFs' views on justification by faith. Here is another http://www.apuritansmind.com/justification/the-early-church-and-justification-compiled-by-dr-c-matthew-mcmahon/. Some quotes from it are:
Jerome (347-420) on Romans 10:3: “God justifies by faith alone.” (Deus ex sola fide justificat). In Epistolam Ad Romanos, Caput X, v. 3, PL 30:692D.
Jerome (347-420): “He who with all his spirit has placed his faith in Christ, even if he die in sin, shall by his faith live forever.” Jacques Le Goff, The Birth of Purgatory, trans. Arthur Goldhammer (Chicago, Illinois: The University of Chicago Press, 1984), p. 61.
Pope Boniface to Caesarius: “[Phil. 1:29]–it appears obvious that our faith in Christ, like all good things, comes to individuals from the gift of divine grace and not from the power of human nature. We rejoice that your brotherhood perceived this truth in accordance with catholic faith, when a council of some bishops of Gaul was held. As you have indicated, they decided unanimously that our faith in Christ is conferred on men by the intervention of divine grace. They added that there is absolutely nothing good in God’s eyes that anyone can wish, begin, do, or complete without the grace of God, for as our Savior said, “Without me you can do nothing” [John 15:5]. For it is both a certainty and an article of catholic faith that in all good things, the greatest of which is faith, divine mercy intervenes for us when we are not yet willing [to believe], so that we might become willing; it remains in us when we are willing [to believe]; and it follows us so that we remain in faith.” William E. Klingshirn, trans., Caesarius of Arles: Life, Testament, Letters, Letter 20 – Pope Boniface to Caesarius; 2 (Liverpool: University Press, 1994), p. 125.
Cyril of Alexandria (412-444): “Seeing then that the law condemned sinners and sometimes imposed the supreme penalty on those who disregarded it and was in no way merciful, how was the appointment of a truly compassionate and merciful high priest not necessary for those on earth; one who would abrogate the curse, check the legal process, and free the sinners with forgiving grace and commands based on gentleness? ‘I,’ says the text, ‘I am he who blots out your transgressions for my own sake, and I will not remember your sins’ (Is. 43:25). For we are justified by faith, not by works of the law, as Scripture says (Gal. 2:16). By faith in whom, then, are we justified? Is it not in him who suffered death according to the flesh for our sake? Is it not in one Lord Jesus Christ? Against Nestorius in Norman Russell, Cyril of Alexandria (London: Rutledge, 2000), p. 165.
Hilary of Poitiers (c 315-67) on Matthew 20:7: “Wages cannot be considered as a gift, because they are due to work, but God has given free grace to all men by the justification of faith.” George Finch, A Sketch of the Romish Controversy (London: G. Norman, 1831), p. 230.
Basil of Caesarea (329-379): “Let him who boasts boast in the Lord, that Christ has been made by God for us righteousness, wisdom, justification, redemption. This is perfect and pure boasting in God, when one is not proud on account of his own righteousness but knows that he is indeed unworthy of the true righteousness and is (or has been) justified solely by faith in Christ. Chemnitz, Examination of the Council of Trent, Part 1, p. 505,
Ambrose (c. 339-97): “Thus I do not have the wherewithal to enable me to glory in my own works, I do not have the wherewithal to boast of myself, and so I will glory in Christ. I will not glory because I have been redeemed. I will not glory because I am free of sins, but because sins have been forgiven me. I will not glory because I am profitable or because anyone is profitable to me, but because Christ is an advocate in my behalf with the Father, because the blood of Christ has been poured out in my behalf.” FC, Vol. 65, Saint Ambrose, Seven Exegetical Works, Jacob and the Happy Life, Book 1, 6.21 (Washington, D.C.: The Catholic University of America Press, 1972), p. 133.
Ambrose (c. 339-97): “I have nothing, therefore, whereby I may glory in my works; I have nothing to boast of, and, therefore, I will glory in Christ. I will not glory because I am righteous, but because I am redeemed. I will not glory because I am free from sin, but because my sins are pardoned. I will not glory because I have done good to any one, or any one has done good to me, but because Christ is my advocate with the Father, and because Christ’s blood was shed for me.” George Finch, A Sketch of the Romish Controversy (London: G. Norman, 1831), p. 220.
Ambrose (c. 339-97): “Therefore let no one boast of his works, because no one can be justified by his works; but he who is just receives it as a gift, because he is justified by the washing of regeneration. It is faith, therefore, which delivers us by the blood of Christ, because blessed is he whose sins are forgiven, and to whom pardon is granted.” George Finch, A Sketch of the Romish Controversy (London: G. Norman, 1831), p. 220.
Augustine (354-430): “But what about the person who does no work (Rom 4:5)? Think here of some godless sinner, who has no good works to show. What of him or her? What if such a person comes to believe in God who justifies the impious? People like that are impious because they accomplish nothing good; they may seem to do good things, but their actions cannot truly be called good, because performed without faith. But when someone believes in him who justifies the impious, that faith is reckoned as justice to the believer, as David too declares that person blessed whom God has accepted and endowed with righteousness, independently of any righteous actions (Rom 4:5-6). What righteousness is this? The righteousness of faith, preceded by no good works, but with good works as its consequence.” John E. Rotelle, O.S.A., ed., WSA, Part 1, Vol. 11, trans. Maria Boulding, O.S.B., Expositions of the Psalms 1-32, Exposition 2 of Psalm 31, ¡±7 (Hyde Park: New City Press, 2000), p. 370.
One piece that I think is quite relevant here in the discussion of what the early church did or did not believe is that we can look at the books of the New Testament, in the order of when they were written and it can help us understand how the Apostles interpreted the writings of the earlier books. "Galatians is widely thought to be the earliest New Testament document or one of the earliest. And Paul’s letters circulated widely early on and were highly regarded even before the apostolic generation came to a close (Colossians 4:16, 2 Peter 3:15-16, etc.). If somebody like Luke or John wrote fifteen, thirty, or more years after Galatians was written, then we can take what he wrote as an indication of how he interpreted Galatians or would have interpreted it if he’d read it (assuming apostolic unity, which conservative Catholics and Evangelicals do). It’s not as though we have to wait until the patristic era to get some idea of how a book like Galatians was being interpreted early on. A portion of the New Testament can be a line of evidence as to how another portion of the New Testament was being interpreted. What does Acts or the gospel of John, for example, suggest about how Galatians was interpreted early on? Or how do Paul's later letters suggest that an earlier letter, like Galatians, should be read?" (from http://triablogue.blogspot.com/2009/12/how-was-john-35-interpreted-prior-to.html)
This demonstrates to me that we can go to the Scriptures - since they are the Divinely-inspired words of God - to know all about the doctrines that the early Christians believed. They WERE being taught directly by the Apostles or their direct disciples, and this, to me, gives far more weight to what is taught than the writings of theologians centuries afterward. Scripture IS our authority. The Christian church is supposed to be the supporter and buttress of the truth - but, unless their teachings are confirmed by Scripture, they do not take the place OF Scripture. They cannot supersede God's word.