"Though Your Sins Be as Scarlet": The Colour That Undoes Itself
Old Testament: Isaias 1:16-18
Wash yourselves, be clean, take away the evil of your devices from my eyes: cease to do perversely... And then come, and accuse me, saith the Lord: if your sins be as scarlet, they shall be made as white as snow: and if they be red as crimson, they shall be white as wool.
New Testament: Apocalypse 7:13-14; Apocalypse 19:13
... These are they who are come out of great tribulation, and have washed their robes, and have made them white in the blood of the Lamb... And he was clothed with a garment sprinkled with blood: and his name is called, THE WORD OF GOD.
The connection
Isaias states the promise as a bare paradox and leaves it unexplained, sin coloured scarlet made white, with no mechanism given for how staining becomes cleansing. John supplies exactly the missing mechanism, and it is stranger than anyone reading Isaias alone could have guessed: the whitening does not happen by scarlet being removed, but by a different red being applied. The great multitude's robes are washed white "in the blood of the Lamb," red used to erase red, the very substance that should stain becoming the thing that cleanses. The two robes in the Apocalypse complete the picture. The redeemed wear robes made white by being washed in the Lamb's blood (7:14); Christ Himself, a few chapters later, wears a robe not washed but "sprinkled with blood" (19:13), stained with the very blood that whitens everyone else. The source and the effect stand side by side in the same book: His garment carries the stain so that every other garment can carry none.
Moral sense
Nobody in Isaias's audience could wash scarlet out with more washing; the text itself frames it as something only the Lord can do ("saith the Lord"). The multitude in white did not scrub their own robes clean; they washed them in a blood that was not their own to give.
Anagogical sense
Reconciliation with God was "acquired for us at the price of his blood" (CCC 1442), not a metaphor added after the fact, but the very mechanism Isaias's paradox was waiting eight centuries to receive an answer for.
The Fathers
St Clement of Rome, First Epistle to the Corinthians, ch. 8, is the earliest Christian use of the promise: though sins “be like scarlet, I will whiten them like wool.” He cites it for repentance rather than for the washed robes of the Apocalypse, so it supports the Isaian half of this entry and not the connection itself.
Warrant
The paradox connecting these two texts is a widely recognised reading, but I could not confirm a specific Father's commentary explicitly tying Isaias 1:18 to Apocalypse 7:14. Checked in the Greek, and the verb is the hinge: Isaias 1:18 promises leukano, I will make white, and Apocalypse 7:14 reports eleukanan, they made white, the same verb in promise and in fulfilment. Eusebius and Theodoret of Cyrus, commenting on Isaias 1:16 to 18, both take the washing to be Baptism, the laver of regeneration of Titus 3:5, and Theodoret has God promise to work like a dyer who makes the red snow white by the bath of Baptism; this supplies the mechanism Isaias leaves unstated, though neither of them cites the Apocalypse.
Catechism of the Catholic Church, paragraph 1442.
The verses
Isaias 1:16 · Isaias 1:17 · Isaias 1:18 · Apocalypse 7:13 · Apocalypse 7:14 · Apocalypse 19:13
