Musnad Ahmad 1167:30

Yahya ibn Sa’id narrated to us, from Ibn Jurayj, who said: ‘Abdullah, the freed slave of Asma’, informed us, from Asma’, that she stopped at the house of Al-Muzdalifah. She said: “O my son, has the moon set on the night of Jam’?” while she was praying. I said: “No.” So she prayed for a while, then said: “O my son, has the moon set?” He said: And the moon had set. I said: “Yes.” She said: “Then depart.” So we departed, and we proceeded with her until we stoned the Jamrah. Then she returned and prayed the morning prayer at her dwelling. I said to her: “O little woman, we have certainly left in the darkness (before dawn).” She said: “Not at all, O my son. The Prophet of Allah, peace and blessings of Allah be upon him, gave permission to the women.”