Musnad Ahmad 25:75

Sufyan narrated to us, from ‘Amr, from Kurayb, from Ibn ‘Abbas: "I spent the night at the house of my maternal aunt, Maymunah. The Prophet, peace and blessings of Allah be upon him, stood up during the night. He said: So he performed a light ablution, then he stood up. Ibn ‘Abbas did as he had done, then he came and stood and prayed. He [the Prophet] moved him and placed him on his right side. Then he prayed with the Prophet, peace and blessings of Allah be upon him, then he lay down until he breathed heavily [in sleep]. Then the mu'adhdhin came to him, and he stood up for the prayer and did not perform ablution."