Romans 4:2-5

2For if Abraham has been justified on the principle of works, he has whereof to boast: but not before 1God;

3for what does the scripture say? And Abraham believed 2God, and it was reckoned to him as righteousness.

4Now to him that works the reward is not reckoned as of grace, but of debt:

5but to him who does not work, but believes on him who justifies the ungodly, his faith is reckoned as righteousness.