Musnad Ahmad 1272:6

Yazid narrated to us, he said: Hammad ibn Salamah narrated to us, from Simak ibn Harb, from Harun, the son of the daughter of Umm Hani—or the son of Umm Hani—from Umm Hani, who said: The Messenger of Allah (peace and blessings of Allah be upon him) entered upon me and asked for a drink, so he was given a drink. He drank, then he handed the remainder to me, and I drank. I said: "O Messenger of Allah, I was fasting, and I disliked rejecting your leftover." He said: "Were you making up a day?" I said: "No." He said: "Then there is no harm upon you."