Come now, and let us reason together,
says 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.
All Commentaries on Isaiah 1:18 Go To Isaiah 1
Augustine of Hippo
AD 430
Humankind has need of God’s grace not only to be made just when they are wicked, when they are changed, that is, from wicked to just, and when they are given good in return for evil, but grace must accompany them, and they must lean on it in order not to fall. This is why it is written of the church in the Song of Songs: “Who is this that comes up clad in white, leaning upon her kinsman?” For she who could not do this of herself has been made white. And who has made her white but him who says by the prophet, “If your sins be as scarlet, they shall be made white as snow”? She was not gaining any good merit then at the time she was made white. But now that she has been made white, she walks aright, provided only that she continues to lean upon him who made her white. Accordingly, Jesus himself, upon whom the church leans, now that she has been made white, said to his disciples, “Without me you can do nothing.”