“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.” (2Cor. 5:21)
The Bible says in Romans 5:11, that through Jesus Christ “we have now received the atonement”. The word “atonement” actually means “the exchange”.
Through the crucifixion of Jesus Christ on the cross of Calvary, Jesus exchanged his perfect life for our sinful life; and through the cross we exchange our sinful life with all of its punishments and curses for His perfect life with all of its blessings, righteousness, and rewards.