Musnad Ahmad 1167:55

Muhammad ibn Bakr narrated to us, he said: Ibn Jurayj informed us, and Rawh said: Ibn Jurayj narrated to us, he said: Abdullah, the freed slave of Asma bint Abi Bakr, informed us, from Asma bint Abi Bakr, that she said: "O my son, has the moon set on the night of Jam' (Muzdalifah)?" I said: "No." Then she said: "O my son, has the moon set?" I said: "Yes." She said: "Then depart." So we departed, and we proceeded until she threw the pebbles at the Jamrah, then she returned and prayed the morning prayer in her dwelling. I said to her: "We have done it in the darkness (before dawn)." Rawh said: "O little one (or O you)." She said: "No, O my son, for the Prophet of Allah gave permission to the women."