Musannaf Ibn Abi Shayba 18:1027

Abu Bakr narrated to us, he said: Ibn 'Uyaynah narrated to us, from 'Abd al-Karim, from Ziyad ibn Abi Maryam, from Ibn Ma'qil, that he said to him: "Did you hear your father say: 'I heard 'Abdullah say: I heard the Prophet, may Allah bless him and grant him peace, say: "Repentance is remorse"?'" He said: "Yes."