Musnad Ahmad 31:305

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, from al-Agharr, who said: I bear witness regarding Abu Hurayrah and Abu Sa‘id al-Khudri that they both bore witness regarding the Prophet, may Allah bless him and grant him peace, that he said: "Indeed, Allah, the Almighty and Majestic, grants respite until the first third of the night has passed, then He descends and says: 'Is there any petitioner? Is there any repentant? Is there any seeker of forgiveness? Is there any sinner?'" He said: A man said to him: "Until the dawn breaks?" He said: "Yes."