سنن ابن ماجه

It was narrated that Ibn Ma’qil said: “I entered with my father upon ‘Abdullah, and I heard him say: ‘The messenger of Allah (ﷺ) said: “Regret is repentance.” My father said: ‘Did you hear the Prophet (ﷺ) say: “Regret is repentance?” He said: ‘Yes.’”