Sunan An-Nasai, Chapter: The Book of the Times (of Prayer)

Abu Yahya Sulaim bin Amr, Damrah bin Habib and Abu Talhah Nuaim bin Ziyad said: "We heard Abu Umamah Al-Bahili say: 'I heard Amrah bin Abasah say: I said: 'O Messenger of Allah, is there any moment which brings one closer to Allah than another, or any moment that should be sought out for remembering Allah?' He said: 'Yes, the closest that the Lord is to His slave is in the last part of the night, so if you can be among those who remember Allah at that time, then do so. For prayer is attended and witnessed (by the angels) until the sun rises, then it rises between the two horns of the Shaitan, that is the time when the disbelievers pray, so do not pray until the sun has risen to the height of a spear and its rays have disappeared. Then prayer is attended and witnessed (by the angels) until the sun is directly overhead at midday, and that is the time when the gates of Hell are opened and it is stoked up. So do not pray until the shadows appear. Then prayer is attended and witnessed (by the angels) until the sun sets, and it sets between the horns of a Shaitan, and that is the time when the disbelievers pray.'" (Sahih)