Ephesians 2:8-10 (ESV) For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, 9 not a result of works, so that no one may boast. 10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
Galatians 2:14-21 (ESV) But when I saw that their conduct was not in step with the truth of the gospel, I said to Cephas before them all, “If you, though a Jew, live like a Gentile and not like a Jew, how can you force the Gentiles to live like Jews?” 15 We ourselves are Jews by birth and not Gentile sinners; 16 yet we know that a person is not justified by works of the law but through faith in Jesus Christ, so we also have believed in Christ Jesus, in order to be justified by faith in Christ and not by works of the law, because by works of the law no one will be justified. 17 But if, in our endeavor to be justified in Christ, we too were found to be sinners, is Christ then a servant of sin? Certainly not! 18 For if I rebuild what I tore down, I prove myself to be a transgressor. 19 For through the law I died to the law, so that I might live to God. 20 I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me. 21 I do not nullify the grace of God, for if righteousness were through the law, then Christ died for no purpose.
"But he said to me, “My grace is sufficient for you, for my power is made perfect in weakness.” Therefore I will boast all the more gladly of my weaknesses, so that the power of Christ may rest upon me. For the sake of Christ, then, I am content with weaknesses, insults, hardships, persecutions, and calamities. For when I am weak, then I am strong." 2 Corinthians 12:9-10 (ESV)