How does Christ's righteousness relate to our justification?

In 2 Corinthians 5:21, it says that God made Christ, who knew no sin, to be sin for us, so that we might be made the righteousness of God in Him. This means that at the moment of faith, Christ's perfect righteousness is credited to us, replacing our guilt before God. Thus, our justification is secure, not based on our own righteousness but on the perfect obedience of Christ. This exchange is at the heart of the gospel, emphasizing that our standing before God hinges entirely on what Christ has accomplished for us.