When the Giver Says Let It Not Atone

One who says, "let his sin offering not atone for him" — Abaye says it does not atone, and Rava says it does atone. Where he said "let it not be offered," all agree it does not atone; what is the reason? Because it is written, "he shall offer it of his own will." But where they disagree is where he said, "let it be offered, but let it not atone." Abaye says it does not atone, since he said "let it not atone." Rava says it does atone: since he said "let it be offered," atonement comes of its own accord. And Rava later retracted his view.