Musannaf Ibn Abi Shayba 13:886

Abu Bakr narrated to us, he said: Muhammad ibn Maysar Abu Sa’d narrated to us, from Musa ibn ‘Ali, from his father, that Ubayy ibn Ka’b used to teach a blind man, and whenever he would come to him, he would provide him with breakfast. He said: So I felt something in myself regarding that, and I asked the Messenger of Allah, peace and blessings of Allah be upon him. He said: "If it is something he is gifting you with, then there is no good in it. But if it is from his food and the food of his family, then there is no harm."