Musnad Ahmad 1153:1517

Waki’ narrated to us, from Hisham ibn ‘Urwah, from his father, from ‘Aishah, who said: When {And warn your closest kindred} [Ash-Shu’ara: 214] was revealed, the Prophet, may Allah bless him and grant him peace, stood up and said: "O Fatimah bint Muhammad, O Safiyyah bint ‘Abd al-Muttalib, O children of ‘Abd al-Muttalib, I possess no power to avail you against Allah in anything. Ask me of my wealth whatever you wish."