But Moses said to the Lord, “Oh, my Lord, I am not eloquent, either in the past or since you have spoken to your servant, but I am slow of speech and of tongue.” Then the Lord said to him, “Who has made man's mouth? Who makes him mute, or deaf, or seeing, or blind? Is it not I, the Lord? Now therefore go, and I will be with your mouth and teach you what you shall speak.” But he said, “Oh, my Lord, please send someone else.” Then the anger of the Lord was kindled against Moses and he said, “Is there not Aaron, your brother, the Levite? I know that he can speak well. Behold, he is coming out to meet you, and when he sees you, he will be glad in his heart. You shall speak to him and put the words in his mouth, and I will be with your mouth and with his mouth and will teach you both what to do. He shall speak for you to the people, and he shall be your mouth, and you shall be as God to him.

The Lord said to Aaron, “Go into the wilderness to meet Moses.” So he went and met him at the mountain of God and kissed him. And Moses told Aaron all the words of the Lord with which he had sent him to speak, and all the signs that he had commanded him to do. Then Moses and Aaron went and gathered together all the elders of the people of Israel. Aaron spoke all the words that the Lord had spoken to Moses and did the signs in the sight of the people. And the people believed; and when they heard that the Lord had visited the people of Israel and that he had seen their affliction, they bowed their heads and worshiped. (ESV)