From Sahih Muslim (Hadith 4579):
It is narrated on the authority of 'A'isha who said:When the Messenger of Allah (ﷺ) passed away, his wives made up their minds to send 'Uthman b. 'Affan (as their spokesman) to Abu Bakr to demand from him their share from the legacy of the Prophet (ﷺ). (At this), A'isha said to them: Hasn't the Messenger of Allah (ﷺ) said:" We (Prophets) do not have any heirs; what we leave behind is (to be given in) charity"?
Reference: Muslim 4579