Musannaf Ibn Abi Shayba 7:424

Abu Khalid narrated to us, from Ibn ‘Ajlan, from al-Muttalib ibn al-Sa’ib ibn Abi Wada’ah, from Sa’id ibn al-Musayyib, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "I broke my fast on a day of Ramadan." The Prophet, may Allah bless him and grant him peace, said to him: "Give charity, seek forgiveness from Allah, and fast a day in its place."