On the authority of Hadrat Anas (may Allāh be pleased with him) who said: I heard Allāh's Prophetic Messenger (may Allāh's blessings and peace be upon him) say:
Allāh the Almighty said: O Son of Ādam, so long as you call upon Me and ask of Me, I shall forgive you for what you have done, and I shall not mind. O son of Ādam, were your sins to reach the clouds of the sky and were you then to ask for forgiveness of Me, I would forgive you; O son of Ādam, were you to come to Me with sins nearly as great as the earth and were you then to face Me, ascribing no partner to Me, I would bring you forgiveness nearly as great as it.
(Tirmidhī) (Hadīth Qudsī)