The Qur'an

Malik :: Book 15 : Hadith 15.10.49

Yahya related to me from Malik from Abdullah ibn Dinar from Abdullah ibn Umar that Umar ibn al-Khattab used to say, "Do not intend to do your prayer at either sunrise or sunset, for the horns of Shaytan rise with the rising of the sun and set with its setting."

Umar used to beat people for that kind of prayer.