Isaiah 43:25

The Lord Himself (cf. Isaiah 43:11) would forgive His people for His own sake, not because they had earned forgiveness with their worship. Forgiveness of sin is a divine prerogative (cf. Matthew 9:2-6). He pictured forgiveness as erasing something previously written on a record (cf. Isaiah 44:22; 2 Kings 21:13; Psalms 51:1; Psalms 51:9). Another figure, forgetting sins committed against Himself, strengthens the promise of forgiveness (cf. Jeremiah 31:34; Micah 7:18-19). Since God is omniscient He never forgets anything, but in this promise He compared Himself to a person who does forget things (an anthropomorphism, cf. Isaiah 43:24) to illustrate the fact that He would not hold their sins against them. He would not call their sins to mind with a view to punishing them. It was sin, not captivity, that was the root trouble that needed dealing with. Later, Isaiah revealed that God would deal with it through His Servant’s ministry (Isaiah 53:10-12).