The freed slave of Usama bin Zaid said,"Al-Hajjaj bin Aiman bin Um Aiman and Aiman IbnUm Aiman was Usama's brother from the maternal side, and he was one ofthe Ansar. He was seen by Ibn 'Umar not performing his bowing andprostrations in a perfect manner. So Ibn 'Umar told him to repeat hisprayer.