Did you ever play “password”? Each word on the list is obscured by red marks so you can’t read it. That is, until you insert the list into the blue plastic sheath. Then the red screen neutralizes the marks and reveals the true shape of the original words.
Take this as a picture of a human being marred by sin. But when that one is “in Christ” and covered by His blood, all that God sees is what He originally intended that person to be. No more ugly defacing sin—only Christ’s righteousness!