Musnad Ahmad 27:835

'Abd al-Rahman narrated to us, from Sufyan, from 'Abdullah ibn Dinar, from Ibn 'Umar, who said: "We used to avoid much speech and familiarity with our women during the time of the Messenger of Allah, may Allah bless him and grant him peace, for fear that the Qur'an might be revealed concerning us. But when the Messenger of Allah, may Allah bless him and grant him peace, died, we spoke."