Sayyiduna Ali (may Allah be pleased with him) narrates that when the Prophet (peace and blessings be upon him) sent me to Yemen, I said to the Prophet (peace and blessings be upon him), "You are sending me to judge among a people who are older than me." He said: "Allah will guide your tongue to the right path, and will keep your heart firm."
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 1342