Sayyiduna Ali (may Allah be pleased with him) narrates that when the Prophet (peace and blessings be upon him) sent me to Yemen, I was young at that time. I said to the Prophet (peace and blessings be upon him), "You are sending me to a people among whom there are differences and disputes, and I have absolutely no knowledge of making judgments?" He said: "Allah will guide your tongue to the right path and will strengthen your heart." Sayyiduna Ali (may Allah be pleased with him) says that after that, I never had any doubt in making decisions between two people.
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 666