“The wrath of the Lord was enflamed against Moses, and He said: Surely Aaron your brother the Levite, I know that he can speak. And behold, he is coming out to meet you, and he will see you, and be glad in his heart” (Exodus 4:14). What enflamed wrath was there? [At that moment,] the priesthood was taken from Moses and given to Aaron. Our Rabbis of blessed memory say: “Surely Aaron your brother the Levite” – from the fact that He said “your brother,” don’t I know that he is a Levite?
Rather, He said to him: ‘You were fit to be a priest, and he, a Levite. Because you refuse to fulfill My words, you will be a Levite, and he, a priest.’ “I know that he can speak.” Because you said: “I am not a man of words,” therefore, he will speak.
And that which you thought that he would be upset, that is not so; rather, he will be glad, as it is stated: “He will see you, and be glad in his heart.” Rabbi Shimon ben Rabbi Yosei said: The heart that was glad over the greatness of his brother will don the Urim ve’Tumim,37Part of the priestly vestments used as an oracle. as it is stated: “They shall be upon Aaron’s heart” (Exodus 28:30). “You shall speak to him and place the words in his mouth, and I will be with your mouth and with his mouth, and I will instruct you what you shall do.
He shall speak for you to the people and he shall be a mouth for you, and you shall be in God’s stead for him” (Exodus 4:15–16). When you fear to speak all these matters, “I will be with your mouth.” “He shall speak for you to the people and he shall be a mouth for you” – a spokesperson. “And you shall be in God’s stead for him.”
Even though he is your older brother, fear of you will be upon him. From here they said: Fear of your teacher is like the fear of Heaven. He [God] said to him: ‘Just as fear of Me is upon you, so, too, fear of you is upon him.’ “You shall take in your hand this staff, with which you shall perform the signs” (Exodus 4:17).
“You shall take in your hand this staff.” You said: “I am not a man of words” (Exodus 4:10). “A slave will not be admonished with words” (Proverbs 29:19). What does one do to a slave?
One afflicts him with a staff. So should you take the staff with which to afflict him; that is what is written: “You shall take in your hand this staff, with which you will perform the signs.”