Musnad Ahmad 1153:176

Abu Mu'awiyah narrated to us, Ibn Jurayj and Yahya narrated to us, meaning from Ibn Jurayj, who said: I heard Ibn Abi Mulaykah, from Dhakwan Abu 'Amr, the freed slave of 'Aishah, from 'Aishah, who said: The Messenger of Allah (ﷺ) said: "Seek the permission of women regarding their private parts." It was said: "But the virgin is too shy to speak?" He said: "Her silence is her permission."