Exodus 4:10-16

Moses said: "I beg you, O Lord, I was not eloquent yesterday or the day before. And from the time that you have spoken to your servant, I have a greater impediment and slowness of tongue." The Lord said to him: "Who made the mouth of man? And who has formed the mute and the deaf, the seeing and the blind? Was it not I? Go on, therefore, and I will be in your mouth. And I will teach you what you shall say." But he said, "I beg you, O Lord, send whomever else you would send." The Lord, being angry at Moses, said: "Aaron the Levite is your brother. I know that he is eloquent. Behold, he is going out to meet you, and seeing you, he will rejoice in heart. Speak to him, and put my words in his mouth. And I will be in your mouth and in his mouth, and I will reveal to you what you must do. He will speak for you to the people, and he will be your mouth. But you will be with him in those things that pertain to God.