Instead of a mouth - We may bear in mind Aaron's unbroken habitude of speaking Hebrew and his probable familiarity with Egyptian.

Instead of God - The word "God" is used of persons who represent the Deity, as kings or judges, and it is understood in this sense here: "Thou shalt be to him a master."

He shall be thy spokesman - Literally, He shall speak for thee (or in thy stead) to the people.

He shall be to thee instead of a mouth - He shall convey every message to the people; and thou shalt be to him instead of God - thou shalt deliver to him what I communicate to thee.

And he shall be thy spokesman unto the people,.... And open to them Moses's commission from God, and the end of his mission into Egypt, and to them, and declare what signs had been, and would be done, in confirmation of it:

and he shall be, even he shall be to thee instead of a mouth; or an interpreter, as all the Targums explain it, and so Jarchi; as he was an orator and master of language, he should speak to the people for Moses, and explain his sense and meaning, and put it into plain, proper, easy language, to be understood by the people; and this may be done where a different language is not spoken, but the same in plainer words, in more pertinent expressions, and better pronounced, and this is repeated for the certainty of it:

and thou shall be to him instead of God; Aaron was to stand between Moses and the people, and speak for him; and Moses was to stand between God and Aaron, and in God's stead, and tell him what orders he had received from him, and which he should communicate; and so some Jewish writers (a) interpret it of his being to him instead of a master or teacher, one that received doctrine from the Lord, and instructed him in it, and taught him the mind and will of God: or, as Onkelos paraphrases it; "for a prince", and so Jarchi, a civil magistrate, one that had the power of life and death; the administration of civil affairs belonged to Moses, and Aaron, though the elder brother, was subject to him; and in this sense Moses was a god to him; and so in after times, the judges of Israel, they that sat in Moses's chair, were called gods, Psalm 82:1.

(a) Targum Jon. Jerus. & Abendana in loc.

And he shall be thy spokesman unto the people: and he shall be, even he shall be to thee instead of a mouth, and thou shalt be to him instead of {g} God.

(g) Meaning, as a wise counsellor and full of God's spirit.

4:16 Instead of God - To teach and to command him.

4:10-17 Moses continued backward to the work God designed him for; there was much of cowardice, slothfulness, and unbelief in him. We must not judge of men by the readiness of their discourse. A great deal of wisdom and true worth may be with a slow tongue. God sometimes makes choice of those as his messengers, who have the least of the advantages of art or nature, that his grace in them may appear the more glorious. Christ's disciples were no orators, till the Holy Spirit made them such. God condescends to answer the excuse of Moses. Even self-diffidence, when it hinders us from duty, or clogs us in duty, is very displeasing to the Lord. But while we blame Moses for shrinking from this dangerous service, let us ask our own hearts if we are not neglecting duties more easy, and less perilous. The tongue of Aaron, with the head and heart of Moses, would make one completely fit for this errand. God promises, I will be with thy mouth, and with his mouth. Even Aaron, who could speak well, yet could not speak to purpose, unless God gave constant teaching and help; for without the constant aid of Divine grace, the best gifts will fail.