Sayyiduna Abdullah bin al-Sa'di (may Allah be pleased with him) narrated that he came to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) during his caliphate. Sayyiduna Umar (may Allah be pleased with him) said to him: "Have I not been told that you take charge of some of the people's affairs, and when you are given the wage, you dislike it?" I said: "Yes, indeed." Sayyiduna Umar (may Allah be pleased with him) said: "What do you intend by that?" I said: "I have horses and slaves, and I am well off, and I want my wage to be charity for the Muslims." Sayyiduna Umar (may Allah be pleased with him) said: "Do not do so, for I too had wanted that. The Messenger of Allah (peace and blessings be upon him) used to give me a gift and I would say: Give it to someone in greater need of it than me. Until once he (peace and blessings be upon him) gave me some wealth, and I said: Give it to someone in greater need of it than me. So the Messenger of Allah (peace and blessings be upon him) said: 'Take it and keep it as your property, or give it in charity. Whatever comes to you of this wealth while you are neither eager for it nor asking for it, take it; and whatever does not come that way, do not let yourself pursue it.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 13015