A simple look to the thoughts and ideas of many Christians suggests that the idea of righteousness by works, i.e. self-righteousness, is very well rooted in many Christian minds. However, the Scripture does not support this idea. Indeed, what the Scripture points out is not our ability to achieve a right standing before God but the sacrifice of Christ who achieved this right standing for us. I Corinthians 1:30 tells us about Christ's accomplishments on our behalf:
1 Corinthians 1:30
"It is because of him [meaning God] that you are in Christ Jesus....."
As we see, it is BECAUSE OF HIM, meaning God, that we are now in Christ Jesus. It is not because of our worth or our abilities but because of the grace, love and goodness of God that we are in Christ Jesus. In the preceding verse (verse 29) Paul says "so that no-one may boast before him [meaning God]” and then it continues:
1 Corinthians 1:30
"It is because of him that you are in Christ Jesus, who became to us wisdom from God and righteousness and sanctification and redemption. Therefore as it is written "let him who boasts boast in the Lord."
Jesus Christ became to us all these things. He became (past tense). It does not say that WE became to him. Instead HE became to us. He became wisdom from God and righteousness and sanctification and redemption. Do you know why we are righteous, redeemed and holy before God? Because Jesus Christ became to us all these things. When did He become ? When you believed. When you believed with your heart that God raised Jesus from the dead and confessed Him as Lord (Romans 10:9), you were declared righteous, you were saved, you were sanctified. I know, it would have been very logical if God had told us:
"Look, you will do this and that work and then you will be saved, become righteous etc." Although there are many that teach exactly that, the Bible does not teaches it. What the Bible tells us is that to become righteous and saved you need to believe with your heart i.e. to truly believe, in the Lord Jesus Christ and His resurrection and stay in the faith. We are saved by faith through grace.
Ephesians 2:8-9 “For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast.”
In whom shall we boast therefore? Not in our works and achievements but in the Lord who “who became to us wisdom from God and righteousness and sanctification and redemption” (1 Corinthians 1:30)