Musnad Abu Ya'la al-Mawsili 155:96

Abu Hisham al-Rifa'i narrated to us, Hafs narrated to us, al-A'mash narrated to us, from Abu Ishaq, from al-Agharr, from Abu Hurayrah and Abu Sa'id, from the Messenger of Allah (may Allah bless him and grant him peace), who said: "When half of the night or a third of the night has passed, He commands a caller, so he calls out: 'Is there any supplicant so that he may be answered? Is there any asker so that he may be given his request? Is there any seeker of forgiveness so that I may forgive him? Is there any repentant so that his repentance may be accepted?'"