From Sahih Muslim (Hadith 1772):
Abu Huraira reported Allah's Messenger (ﷺ) as saying:Our Lord, the Blessed and the Exalted, descends every night to the lowest heaven when one-third of the latter part of the night is left, and says: Who supplicates Me so that I may answer him? Who asks Me so that I may give to him? Who asks Me forgiveness so that I may forgive him?
Reference: Muslim 1772