سنن ابن ماجه

It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said: “Our Lord, the Blessed and Exalted, descends when one third of the night remains, every night and He says: ‘Who will ask of Me, that I may give him? Who will call upon Me, that I may answer him? Who will ask My forgiveness, that I may forgive him?’ until dawn comes.” Hence they used to prefer voluntary prayers at the end of the night rather than at the beginning.