Musnad Ahmad 941:89

Yahya narrated to us, from Sufyan, Ibrahim ibn 'Uqbah narrated to me, from Kurayb, from Usamah ibn Zayd: That when the Prophet, peace and blessings of Allah be upon him, departed—or flowed—from 'Arafah, he came to the mountain pass which the commanders and caliphs descend. He said: So he urinated, and I brought him water, and he performed a good ablution, between the two ablutions. Then he mounted his riding beast. I said: "The prayer, O Prophet of Allah." He said: "The prayer is ahead of you." He said: So he came to Jam' (Muzdalifah), and he performed the iqamah and prayed the Maghrib. Then the rest of the people did not dismount until he performed the iqamah and prayed the 'Isha.