Musannaf Ibn Abi Shaybah 38755 — the first to do a thing, and who did

Al-Sha'bi said: Sayyiduna Umar (may Allah be pleased with him) haggled with a man over a horse. He mounted the horse to test it, and the horse perished. He said to the man: "Take your horse." The man said: "It is no longer mine." Sayyiduna Umar said: "Appoint an arbitrator between you and me." The man said: "Let us go to Shurayh." Shurayh said: "O Commander of the Faithful, keep what you bought, or return it in the condition in which you took it." Sayyiduna Umar said: "Can the judgment be anything other than this?!" Then he sent him to Kufah as judge. That was the first day he came to know him.