Musnad Ahmad 1153:508

Hashim and Yunus narrated to us, they said: Al-Layth narrated to us, he said: Ibn Shihab narrated to me, from Urwah ibn al-Zubayr and Amrah bint Abd al-Rahman, that Aisha, the wife of the Prophet, may God bless him and grant him peace, said: "I would enter the house for a need, and there would be a sick person in it, and I would not ask about him except while I was passing by. And the Messenger of God, may God bless him and grant him peace, would bring his head in to me while he was in the mosque, and I would comb his hair, and he would not enter the house except for a need." Yunus said: "When he was in I'tikaf."