Musnad Ahmad 1153:1270

Hammad narrated to us, Hisham informed us, from his father, from Aisha, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) was never given a choice between two matters, one of which was easier than the other, but that he chose the easier of the two, as long as it was not a sin. If it were a sin, he would be the furthest of people from it."