Musannaf Ibn Abi Shayba 19:761

Abu Bakr narrated to us, he said: Ibn Mubarak narrated to us, from Hammad ibn Salamah, from Qatadah, from Yahya ibn Ya'mar, who said: "If he has confessed, then he has retracted," meaning the one who confesses to a prescribed punishment (hadd) and then retracts it.