The Holy Prophet, peace and blessings of Allah be upon him, said, “Our Lord, the Blessed, the Superior, comes every night down on the nearest Heaven to us when the last third of the night remains, saying: ‘Is there anyone to invoke Me, so that I may respond to invocation? Is there anyone to ask Me, so that I may grant him his request? Is there anyone seeking My forgiveness, so that I may forgive him?’”
(Sahih al-Bukhari, Kitab al-Tahajud)