NOTES for Isa 43:24-25
So the Lord says that His people forgot everything He had done for them, forgot all His miracles. And again He performs miracles for His people. Why? The people did not cry out to Him, did not offer sacrifices, did not ask for help... All that the people did was hinder God from acting in their lives: they burdened Him with sins and wearied Him with iniquities, as the prophet Isaiah says. Why then does the Lord blot out all iniquities and agree not to remember sins? The answer He gives here is universal. He says: 'For My own sake.' He is ready to forget sins not because the people corrected themselves or asked politely. He forgives because He is good and merciful, because He loves.