Musannaf Ibn Abi Shayba 33:26

Dawud narrated to us, he said: Hammad bin Salamah narrated to us, from Sa'id al-Jurayri, that Dawud said: "O Gabriel, which part of the night is best?" He said: "I do not know, except that I know that the Throne shakes from the time of the pre-dawn (al-sahar)."