Musnad Abu Ya'la al-Mawsili 150:386

Mujahid narrated to us, Mu'adh narrated to us, Ibn Jurayj narrated to us, from Ibn Abi Mulaykah, from Dhakwan, from 'Aishah, who said: The Messenger of Allah (peace be upon him) said: "Seek the permission of women regarding their private parts." They said: "O Messenger of Allah, but the virgin is shy." He said: "Her silence is her consent."