Musnad Ahmad 509:24

Surayj ibn al-Nu‘man narrated to us, ‘Umar ibn Maymun ibn al-Rummah narrated to us, from Abu Sahl Kathir ibn Ziyad al-Basri, from ‘Amr ibn ‘Uthman ibn Ya‘la ibn Murrah, from his father, from his grandfather: "The Messenger of Allah (may Allah bless him and grant him peace) arrived at a narrow pass, he and his companions, while he was upon his riding beast, with the sky above them and the wetness (mud) below them. The time for prayer arrived, so he commanded the mu'adhdhin, who gave the adhan and the iqamah. Then the Messenger of Allah (may Allah bless him and grant him peace) stepped forward upon his riding beast and prayed with them, gesturing with a gesture, making the prostration lower than the bowing, or he made his prostration lower than his bowing."