Musnad Ahmad 1709

It was narrated from Ibn Abu Najeeh that his father told him that someone who heard "AbdurRahman bin Abi Bakr told him that [the latter] said: The Messenger of Allah (ﷺ) said: “Ride this she-camel and put your sister behind you, then when you come down from the hill of at-Tan’eem, both of you should enter ihram and come here." That was on the day when the pilgrims do the tawaf of farewell before leaving Makkah.