‘Abdallah b. ‘Amr b. al-‘As reported God’s Messenger as saying to him, “Don’t be like so and so, ‘Abdallah. He used to get up during the night, then abandoned the practice.”
Abu Malik al-Ash‘ari reported God’s Messenger as saying, “In paradise there are rooms the outside of which can be seen from within and the inside from without which God has prepared for those who speak gently, provide food, observe frequent fasting, and pray during the night when people are asleep.”
Baihaqi transmitted it in Shu'ab al-iman and Tirmidhi transmitted something similar from ‘Ali. In his version it says “for those who speak pleasantly.”
Narrated ‘Uthman b. Abul ‘As said he heard God’s Messenger say:
David had an hour during the night in which he would waken his family and say, “Family of David, get up and pray, for this is an hour in which God who is great and glorious answers petitions, except to a magician or a tax-gatherer.”
Abu Umama said that God’s Messenger was asked which supplication was most readily listened to, and replied, “One made in the course of the latter part of the night, and after the prescribed prayers.”
