Musannaf Ibn Abi Shayba 19:420

Abu Bakr narrated to us, he said: Hushaym narrated to us, from some of his companions, from al-Sha'bi, that a man said to a man: "So-and-so claims that you are an adulterer." He said: "If he brings the evidence, [then it is so]; otherwise, the prescribed punishment (hadd) shall be struck upon him."