Hadith 1315:1
Hisham ibn Sa'id narrated to us, he said: Mu'awiyah ibn Salam informed us, he said: I heard Yahya ibn Abi Kathir, he said: Ba'jah ibn 'Abdullah informed me, that his father informed him that the Messenger of Allah, peace and blessings of Allah be upon him, said to them one day: "This is the day of 'Ashura', so fast." A man from the tribe of Banu 'Amr ibn 'Awf said: "O Messenger of Allah, I left my people, among them are those who are fasting and those who are not fasting." The Prophet, peace and blessings of Allah be upon him, said: "Go to them, and whoever among them is not fasting, let him complete his fast."
حدثنا هشام بن سعيد، قال: أخبرنا معاوية بن سلام، قال: سمعت يحيى بن أبي كثير، قال: أخبرني بعجة بن عبد الله، أن أباه، أخبره أن رسول الله صلى الله عليه وسلم قال لهم يوما: " هذا يوم عاشوراء، فصوموا " فقال رجل من بني عمرو بن عوف: يا رسول الله، إني تركت قومي، منهم صائم، ومنهم مفطر، فقال النبي صلى الله عليه وسلم: " اذهب إليهم، فمن كان منهم مفطرا ، فليتم صومه "