It is narrated from Sayyiduna Abu Sa'd al-Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Remorse is repentance, and the one who repents from sin is like one who has no sin."
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 18979