Musannaf Ibn Abi Shayba 3:2015

Abu Bakr narrated to us, he said: Ali bin Mushir narrated to us, from Dawud bin Abi Hind, from Bakr bin Abdullah, he said: A man came to Umar and said: "So-and-so led us in the Fajr prayer and recited a Surah in which he prostrated." Umar said to him: "Did he really do that?" He said: "Yes." So the next day, Umar prayed and recited [Surah] An-Nahl and [Surah] Bani Isra'il, and he prostrated in both of them.