Eph 1:7, Heb 9:14, Heb 13:12, Rev 7:14
In the Old Testament, Isaiah said that God would cleanse us from our sins. (Isa 1:18)
Isa 1:18 Come now, and let us reason together, saith the Lord: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.
God has made us clean by the blood of Christ. (Heb 9:14, Heb 13:12, Eph 1:7, Rev 7:14)
Heb 9:14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?
Heb 13:12 Wherefore Jesus also, that he might sanctify the people with his own blood, suffered without the gate.
Eph 1:7 In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;
Rev 7:14 And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.