"Allah, Blessed and Exalted, says: 'O son of Adam! As long as you call upon Me and put your hope in Me, I will forgive you for whatever you have done, and I shall not mind. O son of Adam! If your sins were to reach the clouds of the sky, and then you were to ask forgiveness of Me, I would forgive you, and I shall not mind.'"
Jami' at-Tirmidhi 3540 (Hadith Qudsi) — Narrated by Anas ibn Malik (RA)
"All of the children of Adam frequently err, and the best of those who frequently err are those who frequently repent."
Jami' at-Tirmidhi 2499 — Narrated by Anas ibn Malik (RA)