Musnad Ahmad 1153:2241

Ishaq ibn Isa narrated to us, he said: Malik informed us, from al-Zuhri, from Urwah, from Aisha, that the wives of the Prophet, may Allah bless him and grant him peace, when the Messenger of Allah, may Allah bless him and grant him peace, passed away, wanted to send Uthman to Abu Bakr to ask him for their inheritance from the Messenger of Allah, may Allah bless him and grant him peace. Aisha said to them: "Has the Messenger of Allah, may Allah bless him and grant him peace, not said: 'We are not inherited from; what we leave behind is charity'?"