"For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more" (Hebrews 8:12).
The sins of God’s elect are not remembered by the Lord because they were heaped upon Christ, as an awful weight, and He bore them away. Isaiah declared, "All we like sheep have gone astray; we have turned every one to his own way; and the LORD hath laid on Him the iniquity of us all" (Isaiah 53:6). "Laid on Him," means that the sins of all the sheep were gathered together, as though one bundle, and laid on Christ. This was the heaviest of burdens, such as only God could bear. Our sins, having been made to meet upon the head of our Scape-Goat, were then borne away by Him, something the animal sacrifices could never do. "For it is not possible that the blood of bulls and of goats should take away sins" (Hebrews 10:4). The express reason for Christ’s incarnation was to remove the guilt of His people by the sacrifice of Himself. "And ye know that He was manifested to take away our sins; and in Him is no sin" (1 John 3:5). It is because our sins have been washed away in the blood of the Savior that they are not remembered by the Lord. Hear these gracious words of our covenant God. "I, even I, am He that blotteth out thy transgressions for Mine own sake, and will not remember thy sins" (Isaiah 43:25). The sins of God’s children are not remembered by Jehovah; they are forgiven and forgotten. Such is the infinite power of the blood and righteousness of the Lord Jesus that He has completely removed every stain, stench and evidence of sin; nothing of it remains.
On the other hand, the sins of all those for whom Christ did not die will forever be remembered by the Lord. "Thus saith the LORD unto this people, Thus have they loved to wander, they have not refrained their feet, therefore the LORD doth not accept them; He will now remember their iniquity, and visit their sins" (Jeremiah 14:10). The sins of all those who leave this world in unbelief and rebellion are written down in the books, which shall be opened in the final day of judgment. The Lord will not and cannot accept those who are "laden with iniquity" because He is of "purer eyes than to behold evil, and canst not look on iniquity" (Habakkuk 1:13). If sin remains, God remembers it and punishes it, but when sin has been taken away, there can be no condemnation, for there is no iniquity to bring about judgment. Christ removed the sins of His sheep, and God remembers them no more. "In those days, and in that time, saith the LORD, the iniquity of Israel shall be sought for, and there shall be none; and the sins of Judah, and they shall not be found: for I will pardon them whom I reserve" (Jeremiah 50:20).