Musnad Ahmad

It is narrated from Hazrat Usama bin Zaid (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) departed from Arafat and reached the valley where people used to make their mounts sit down. The Noble Prophet also made his she-camel sit there, then he urinated and cleansed himself with water, then he asked for water for ablution and performed ablution, but not excessively. I said, "O Messenger of Allah! The time for prayer has come." The Noble Prophet (peace and blessings be upon him) said, "The prayer is ahead of you." Then he mounted his ride and reached Muzdalifah, where he offered the Maghrib prayer. Then people made their mounts sit at their respective places, and before they could unload their luggage, the Isha prayer was established. He offered the prayer, and did not offer any prayer between the two.