Musannaf Ibn Abi Shayba 35:249

'Abd al-Rahman ibn Mahdi narrated to us, from Hammad ibn Salamah, from 'Ali ibn Zayd, from al-Miswar ibn Makhramah, that he saw a man who was not completing his bowing (ruku') nor his prostration (sujud). So he said to him, "Repeat [it]." But he refused. So he did not leave him until he repeated it. And he mentioned that Abu Hanifah said, "It suffices him, though he has done wrong."