Musannaf Ibn Abi Shaybah 8733 — Those who used to pray on their mounts

Sayyiduna Abu Sa'id and Sayyiduna Ibn Umar (may Allah be pleased with them) said: The Prophet (peace and blessings be upon him) used to pray voluntary prayers on his mount while travelling, whichever direction it faced, and he performed the bowing and prostration by gesture in such a way that the prostration was lower than the bowing.