I heard the Messenger of Allah (may Allah’s peace and blessings be upon him) saying: “Allah, the Exalted, said: ‘O son of Adam, 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 Adam, were your sins to reach the clouds of the sky and were you then to ask forgiveness of Me, I shall forgive you. O son of Adam, were you to come to Me with sins nearly as great as the earth and were you then to meet Me, ascribing no partner to Me, I shall bring you forgiveness nearly as great as it.'”
Narrated by At-Tirmidhi and Ahmad Ad-Daarimi