Does God forget all of our sins once we have confessed and repented of them? Several Scriptures mention that God casts our sins from His sight and blots them out. Hebrews 8:12 even says He will remember them no more.
“For I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more.” Hebrews 8:12 (NKJV)
“As far as the east is from the west, so far has He removed our transgressions from us.”                                  Psalm 103:12 (NKJV)
“I, even I, am He who blots out your transgressions for My own sake; And I will not remember your sins.” Isaiah 43:25 (NKJV)
“He will again have compassion on us, and will subdue our iniquities. You will cast all our sins into the depths of the sea.” Micah 7:19 (NKJV)
Although God chooses to remember our sin no more, it does not mean He forgets our sin. Instead, He recognizes that the blood of His son, Jesus, has covered them. Through Christ, we have a restored relationship with Father God.
Hebrews 10 explains how Jesus’ sacrifice on the cross for sin was a once-and-for-all sacrifice. God no longer remembers our sins because Jesus was the perfect atonement for all sin. However, God does not forget sin. God is omniscient. He is all knowing and forgets nothing. In His mercy and grace, He can choose not to remember something.
Have you heard the saying, “I can forgive but I can’t forget!” I was taught that this attitude was hard-hearted. But the reality is, we are incapable of forgetting wrongs (unless we have medical amnesia). Painful moments are not seared away from memory. Instead, God asks us to forgive wrongdoers by not dwelling on their offense.
We will not actually forget their sin, nor are we incapable of recalling their offense. We merely choose to overlook it. Forgiveness prevents us from brooding over past troubles.
God may choose to use the memory of past sins for corrective purposes and keep us (and others) from further sin. The Holy Spirit brings to memory past wrongs when it serves to correct, educate, or refine us. Peter learned an important lesson in humility after declaring, “Even if I have to die with you, I will never disown you.” Christ recognized his pride and prophesized Peter would deny Him three times before the rooster crowed.
“But Peter declared, ‘Even if I have to die with you, I will never disown you.’ And all the other disciples said the same.” Matthew 26:35 (NIV)
“The Lord turned and looked straight at Peter. Then Peter remembered the word the Lord had spoken to him: “Before the rooster crows today, you will disown me three times.” Luke 22:61 (NIV)
Before the judgment seat of Christ, we will each receive the things done in the body, whether good or bad. If God forgot all sin, how could the bad deeds be recalled at the judgment seat?  We should not look at the judgment seat of Christ as God judging our sins, but rather as God rewarding us for our lives. But, we will have to give an account of ourselves and part of this is surely answering for our sins.
“For we must all appear before the judgment seat of Christ, that each one may receive the things done in the body, according to what he has done, whether good or bad.”  2 Corinthians 5:10 (NKJV)
If someone has sinned against you, make a personal choice now to forgive him or her. This is not an easy task, especially if they have not sought out your forgiveness. But if you choose to hold unforgiveness in your heart, it will hinder your relationship with God and His ability to forgive you.
“For if you forgive men their trespasses, your heavenly Father will also forgive you. But if you do not forgive men their trespasses, neither will your Father forgive your trespasses.” Matthew 6:14-15 (NKJV)
Do not dwell upon the wrongs others have committed against you. Instead, consider what God has forgiven in your life. You cannot possibly list all the wrongs your Creator has cast aside. They are more than you can count! Rather, set your mind on higher things. Yes, it is far better to consider things that are praiseworthy. Dwell upon things that are pure, lovely, and right in the person who has sinned against you. This will stimulate God’s love within your heart and enable you to forgive those whom you thought too hard to forgive.
“Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things.” Philippians 4:8 (NIV)
“Set your mind on things above, not on things on the earth.” Colossians 3:2 (NKJV)
“Be kind and compassionate to one another, forgiving each other, just as in Christ God forgave you.” Ephesians 4:32 (NIV)
“Do not remember the sins of my youth, nor my transgressions; According to Your mercy remember me, for Your goodness’ sake, O Lord.” Psalm 25:7 (NKJV)