Exodus 4:14-18

Then the anger of the Lord burned against Moses, and He said, “Is there not your brother Aaron the Levite? I know that he speaks fluently. And moreover, behold, he is coming out to meet you; when he sees you, he will be overjoyed.

So you are to speak to him and put the words in his mouth; and I Myself will be with your mouth and his mouth, and I will instruct you in what you are to do.

He shall speak for you to the people; and he will be as a mouth for you and you will be as God to him.

And you shall take in your hand this staff, with which you shall perform the signs.”

Then Moses departed and returned to his father-in-law Jethro, and said to him, “Please, let me go, that I may return to my brothers who are in Egypt, and see if they are still alive.” And Jethro said to Moses, “Go in peace.”