What example did the Prophet Muhammad (saw) give when he saw Aiman ibn Um Aiman not performing his prayer in a perfect manner?
 The freed slave of Usama bin Zaid said, "Al-Hajjaj bin Aiman bin Um Aiman and Aiman Ibn      Um Aiman was Usama's brother from the maternal side, and he was one of     the Ansar. He was seen by Ibn 'Umar not performing his bowing and      prostrations in a perfect manner. So Ibn 'Umar told him to repeat his      prayer.