Abu Hariz said that a man used to give Sayyiduna Umar (may Allah be pleased with him) the thigh of a camel as a gift every year. Then he came with a dispute to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) and said: "O Commander of the Faithful! Judge between us, as the thigh of a camel is separated from the camel." So Sayyiduna Umar (may Allah be pleased with him) wrote to his governors: "Do not accept gifts, for they are a bribe."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20476