God said to Moses:
“Verily, I am Allah!  There is no other god except Me.  So worship Me, and perform the prayer for My remembrance.”

     (Quraan, 20:14)

"Allah the Almighty has said: 'O son of Adam, so long as you call upon Me, and hope in 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 in 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 an earthful of sins and were you then to face Me, without having associated anything with Me, I shall grant you an earthful of pardon.'"

     At-Tirmithi