1 John 1:9 says, “If we confess our sins, He is faithful and just and will forgive us our sins and purify us from all unrighteousness.” Isaiah 43:25 says, “I, even I, am He who blots out your transgressions, for my own sake, and remembers your sins no more.”
The Lord treats repentant sin placed under the blood of Christ as if He has completely forgotten the act. (Jamieson, Fausset and Brown) Christians have the assurance that God blots out the sin. This is a metaphor taken from the custom of keeping accounts, where, when a dept is paid, it is blotted out. It is like a drop of ink or in this case, a drop of blood from Christ gets on the recorded account and cannot be read. Notice, I said it is like.
It is important to note that it is not because of what anyone has done. It is because God longs to show His forgiveness as Christ showed His love for us in His obedience unto death. Christians do not rest upon a work of any kind, they may rest upon the ever-loving, never-ending grace of God found in faith in Christ and Christ alone. Lay every sin at the foot of the Cross and trust alone in God’s Word, which reveals Christ, the person of our sure hope.
God forgave King David of the many sins he committed, even though he suffered the consequences of those sins the rest of his life, the Lord used him greatly. The Lord took murderous Saul of the New Testament, and changed him into a great apostle to the gentiles (Romans 11:13; Galatians 2:8; 1 Timothy 2:7) and used him to write most of the New Testament. The Lord took Peter, the one who publicly denied Christ (John 18:12-27) and made him into a great spiritual leader (1 and 2 Peter), it was his type of faith in Christ of which the Lord said, “I will build My church” (Matthew 16:18).
The Lord is taking men and women from all over the world, Jews and Gentiles and calling them to Christ and enabling them to do a great work with Him. He forgave their sins and is using them to preach and teach the Word of God. Churches are being started and sustained. People are being taught the teachings of Christ and the whole counsel of God’s Word. God treated people in the Bible as though he has forgotten their sins and many today can testify of the Lord’s treating them as though He has forgotten their sins.