Returning to God !
Returning to God, which is an aspect of repentance, is premised upon having been redeemed by Christ, and having had
by Christ's blood our sins/transgressions blotted out as a thick cloud Isa 44:22
I have blotted out, as a thick cloud, thy transgressions,
and, as a cloud, thy sins:
return unto me; for I have redeemed thee.
The redemption in and through Christ's Blood brings forgiveness Eph 1:7
7 in whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;
Also the NT fulfillment of Isa 44:22 is found here Col 2:13-14
13 And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses; 14 blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;
Remember God is speaking to His Elect in Isa 44:22 as well as in Col 2:12-13 ; Col 3:12
12 Put on therefore, as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind, meekness, longsuffering; 13 forbearing one another, and forgiving one another, if any man have a quarrel against any: even as Christ forgave you, so also do ye.