Musannaf Ibn Abi Shaybah 34806 — What they said on horses released

Sayyiduna Imran bin Husayn (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Shouting to urge on a horse to run is not permissible, nor is keeping another horse alongside oneself during a race, so that if the first horse tires one may mount the other."