From Sahih Muslim (Hadith 1774):
Abu Huraira reported Allah's Messenger (ﷺ) as saying:When half of the night or two-third of it is over. Allah, the Blessed and the Exalted, descends to the lowest heaven and says: Is there any beggar, so that he be given? Is there any supplicator so that he be answered? Is there any beggar of forgiveness so that he be forgiven? (And Allah continues it saying) till it is daybreak
Reference: Muslim 1774