Musnad Abu Ya'la al-Mawsili 217:8

Suwayd ibn Sa'id narrated to us, Sufyan narrated to us, from 'Abdullah ibn 'Abdullah, the nephew of Yazid ibn al-Asamm, from his paternal uncle, from his maternal aunt, Maymunah, the wife of the Prophet (may Allah bless him and grant him peace), who said: When the Prophet (may Allah bless him and grant him peace) prostrated, if a beast had wished, it could have passed beneath his arms.