Musnad Ahmad 1153:1180

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, from 'Urwah, that 'Aishah said: The Messenger of Allah, peace and blessings of Allah be upon him, used to take the pledge of allegiance from women by speech with this verse: {That they will not associate anything with Allah} [al-Mumtahanah: 12]. She said: "And his hand never touched the hand of a woman at all, except for a woman whom he possessed."