Abu Burdah said: I sat with a man from the Muhajirun, and he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "O people, turn in repentance to Allah and seek His forgiveness, for indeed I turn in repentance to Him a hundred times in a day."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 881