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; Psalm 51:1; Psalm 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). [source][source][source]
Context Summary
Isaiah 43:14-28 - A Way In The Wilderness
Let uptake care lest we thwart God's purpose in our lives. We were made to show forth His praise, Isaiah 43:21; but we must beware of causing a revoking of His gracious purpose (See Numbers 14:34, r.v. margin): by prayerlessness, Isaiah 43:22; by the neglect of little things, Isaiah 43:23; by the lack of sweetness and tenderness in our disposition, Isaiah 43:24. "Be not high-minded, but fear; for if God spared not the natural branches, neither will He spare thee," Romans 11:20-21, r.v.
On the other hand, directly sin is repented of and put away, it is blotted out, Isaiah 43:25. It is persistence in sin that causes God to turn from us. If we forsake what is evil, as soon as we are conscious of it, "the blood of Jesus Christ cleanseth from all sin." It is blotted out as a cloud from the sky and no more remembered against us forever. This is done for God's own sake. The reason for our salvation and deliverance is not in us, but in Him. The cross of shame and sorrow was His own expedient, and the Lamb in the midst of the throne is the emblem of the divine Atonement, which was commenced and finished by the inexplicable grace of God. [source]
Chapter Summary: Isaiah 43
1The Lord comforts the church with his promises 8He appeals to the people for witness of his omnipotence 14He foretells them the destruction of Babylon 18And his wonderful deliverance of his people 22He reproves the people as inexcusable
What do the individual words in Isaiah 43:25 mean?
I[even] I [am]Hewho blots outyour transgressionsfor My own sakeand your sinsnotI will remember