Musannaf Ibn Abi Shaybah 36008 — The affair of al-Qadisiyyah

Al-Sha'bi said: On the occasion of the Battle of al-Qadisiyyah, Sayyiduna Umar (may Allah be pleased with him) wrote a letter to Sayyiduna Sa'd (may Allah be pleased with him) in which he wrote: "I am sending you the people of Hijaz and the people of Yemen. Whoever of them reaches the fighting before the slain burst open, give him a share of the spoils."