Qays bin Abi Hazim said: Sayyiduna Umar (may Allah be pleased with him) gave Jarir (may Allah be pleased with him) and his people a quarter of the Sawad. They collected its kharaj for two or three years. Then Jarir and Ammar bin Yasir (may Allah be pleased with them both) went to Sayyiduna Umar (may Allah be pleased with him), and he said: "O Jarir! If I were not going to be questioned about the distribution, I would have kept you in that same state. But now return it to the Muslims." So Jarir (may Allah be pleased with him) returned the quarter of the Sawad, and in exchange Sayyiduna Umar (may Allah be pleased with him) gave him eighty dinars.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18379