“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”– Isaiah 1:18
This verse is a parenthesis in the midst of Isaiah’s prophecy of rebuke and warning.
We might have expected for Isaiah to speak of how justified God’s judgment would be because of Israel’s sinful rebellion. But he also surprises us with this reasoning from the Lord: “if you turn to God in repentance, then all your past mistakes will be utterly washed away.”
This does not at first sound reasonable, or rational, at all. We all know that an apology cannot undo a wrong that has been committed. Saying one is sorry for adultery or murder does not undo the unfaithfulness or loss. So how then does repentance somehow make our red-handed sins clean and white before God?
The answer, the rationale, from the Lord is found later in this same prophecy. A suffering Servant would come, who would be “wounded for our transgressions;” our chastisement, our punishment would be put upon him, and with his wounds he would heal us, clean us (53:5).
You see, there is nothing you can do to take away your past sins and guiltiness before a holy God. But God has promised, when you turn to him in repentance, that your sin-stains will be washed completely away by the sacrifice of Jesus Christ.
Come now,says the Lord, to hear and consider this promise of forgiveness. Do not distance yourself, but come; do not delay, but come now.(Baptist Bible Hour)