Musannaf Ibn Abi Shaybah 35262 — What they said on branding campaign

Muhammad bin Ubaydullah al-Thaqafi (may Allah have mercy on him) said: Sayyiduna Umar (may Allah be pleased with him) had four thousand horses in a place for tethering livestock in Kufah. All of them had a mark on their thighs showing that they were endowed for the path of Allah. If a man had some right in his annual stipend, or someone was in need, he (may Allah be pleased with him) would give him a horse. Then he would say: "If you run it until it is exhausted, or you ruin it by neglecting its fodder, you will be liable for it. But if you fight on it and harm comes to it or harm comes to you, nothing will be due from you."