Musnad Ahmad 1156:216

'Uthman ibn 'Umar narrated to us, Yunus informed us, from al-Zuhri, he said: Hind bint al-Harith al-Qurashiyyah narrated to me, that Umm Salamah, the wife of the Prophet, may Allah bless him and grant him peace, informed her: "That the women, during the time of the Messenger of Allah, may Allah bless him and grant him peace, would stand up when he finished the obligatory prayer. The Messenger of Allah, may Allah bless him and grant him peace, would remain [seated], and those of the men who prayed would remain [seated] for as long as Allah willed. Then, when the Messenger of Allah, may Allah bless him and grant him peace, stood up, the men would stand up."