When reading this article on Thomas Aquinas, I found this interesting take on justification:
The first work of the grace of the Holy Spirit is conversion, effecting justification in accordance with Jesus’ proclamation at the beginning of the Gospel: ‘Repent, for the kingdom of heaven is at hand.’[Matthew 4:17]. Moved by grace, man turns toward God and away from sin, thus accepting forgiveness and righteousness from on high…The merit of man before God in the Christian life arises from the fact that God has freely chosen to associate man with the work of his grace. The fatherly action of God is first on his own initiative, and then follows man’s free acting through his collaboration, so that the merit of good works is to be attributed in the first place to the grace of God, then to the faithful. Man’s merit, moreover, itself is due to God, for his good actions proceed in Christ, from the predispositions and assistance given by the Holy Spirit.
1. Official Catholic dogma admits that conversion begins as “operating grace,” which means it is solely the act of God. This is certainly correct.
2. The idea of “cooperating grace” need not be unbiblical: “Therefore, my beloved, as you have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling; for it is God who works in you both to will and to do for His good pleasure.” (Phil 2:12-13) Furthermore, read Ezek 18:31 (“Cast away from you all the transgressions which you have committed, and get yourselves a new heart and a new spirit. For why should you die, O house of Israel?”) in light of Ezek 36:26 (“I will give you a new heart and put a new spirit within you; I will take the heart of stone out of your flesh and give you a heart of flesh.)
The problem is the interpretation that the good works we do, while in the flesh, give us “merit” before God. I understand the Bible speaks of us being judged by our deeds, but the Bible also says “there is no one righteous.”
My best understanding is that our own good works do not merit justification, because God does not speak about them in that way: “For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.” (Eph 2:10) God has prepared for us good works that, cooperating with our will but ultimately changing it by His Spirit, we are to do in Christ.
Even in the Bible’s strongest statement saying that we are supposedly justified by works, we see that the plain reading of the text does not allow this conclusion: “Do you see that faith was working together with his works, and by works faith was made perfect?…You see then that a man is justified by works, and not by faith only.” (James 2:22, 24)
James does not question that men are saved by the basis of their faith. He merely argues that faith without works is dead, as in, such faith that is simply made up of “head knowledge.” I would say everyone agrees with that.
However, in this teaching, we see nothing concerning the necessity of accruing merits throughout a lifetime. The Bible says that our good works are prepared for us beforehand, and being that it is God who works through us, justification then is an act of God, not of our own will in any way. Therefore, if justification begins and is at all times completed as an act of God, it is never added to in our lifetime by our works. Rather, works are the evidence that a saving faith is at work in us by God’s grace.