Musannaf Ibn Abi Shaybah

Hazrat Muhammad bin Ubaidullah Thaqafi (may Allah have mercy on him) narrates that Hazrat Umar (may Allah be pleased with him) had four thousand horses in Kufa at the place where livestock were tied. All of them had a mark on their thighs indicating that they were dedicated in the path of Allah. If someone had a right to an annual salary or was in need, he (may Allah be pleased with him) would give him a horse. Then he would say: If you tire it out by making it run excessively or waste it due to its fodder, then you will be responsible for it. But if you fight upon it and it dies, or you die, then nothing will be required from you.