A man from San'a' said: I was in Makkah; we were sitting with Ata' al-Khurasani beside the wall of the mosque. We did not ask him anything, nor did he narrate any hadith to us. The narrator said: Then we went and sat with Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), just as you are sitting now. We did not ask him anything either, nor did he narrate any hadith to us. Then he said: "What is the matter? Why are you not speaking? Why are you not remembering Allah Almighty? Say: 'Allahu akbar' (Allah is the Greatest), 'Alhamdulillah' (praise be to Allah) and 'Subhan Allah wa bihamdihi' (Glory be to Allah and praise be to Him). For one there will be ten, and for ten there will be a hundred. Whoever does more, Allah Almighty will give him more reward, and whoever remains silent, may Allah Almighty forgive him. Shall I not tell you about five things that I heard from the Prophet (peace and blessings be upon him)?" We said: "Yes, indeed!" Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: (The Prophet (peace and blessings be upon him) said:) "Keep up the two rak'ahs of Fajr regularly, for in those two there is much to be desired."
Ahmad recorded it as part of a long hadith, which Abu Dawud also narrated; its chain contains a narrator who is not named.