We are justified through faith in the blood of Jesus. Let’s read what Paul wrote about this in Romans:
Now to him [the religious person] that worketh is the reward not reckoned of grace, but of debt. But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness. (Romans 4:4–5 kjv)
Notice verse 5. The first thing you have to do is to stop trying to make yourself righteous. Stop trying to be a little better. Call a halt to all that. “To him that worketh not.” What should we do? Let’s look again at the end of that passage: “But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness” (verse 5 kjv). Just believe. Is it that simple? If it is not that simple, we will never make it. God makes unrighteous people righteous—that is what the Scripture says, and I believe it.
For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him. (2 Corinthians 5:21 kjv)
I like to change the order of the words in that verse, substituting specific names for the pronouns. “For God has made Jesus, who knew no sin, to be sin for us, that we might be made the righteousness of God in Jesus.” There is the complete exchange. Jesus was made sin with our sinfulness so that we might be made righteous with His righteousness. This righteousness is available through faith in His blood. We are made righteous through faith in the blood of Jesus Christ.