Anas said, “God's Messenger used to break his fast during a month so that we imagined he had not fasted during it at all, and he fasted so that we imagined he had not broken it. You did not wish to see him praying during the night without doing so, or sleeping without doing so.”
Ibn ‘Umar said that his father ‘Umar b. al-Khattab used to pray during the night what God wished, then during the latter part of the night he woke his family for prayer saying to them, “Come to prayer.” Then he would recite this verse, “And command your family to observe the prayer, and be constant in it. We do not ask you for provision; We provide you, and the issue pertains to piety” (Al-Qur'an; 20:132).