John Calvin Commentary Exodus 4:16

"And he shall be thy spokesman unto the people; and it shall come to pass, that he shall be to thee a mouth, and thou shalt be to him as God." — Exodus 4:16 (ASV)

And he shall be your spokesman. God destroys the pretext for his exemption by assigning to his brother the office of spokesman, and yet He does not put the other in his place. No, so merciful is the arrangement that while He yields to His servant’s prayer, He still confers honor on him in spite of himself.

The offices are thus divided: Moses is to have the authority, and Aaron is to be the interpreter. Thus Moses is set above his brother, not out of respect for his own dignity, but because the grace of God was to shine out conspicuously in the head as much as in the members. This is expressed in these words, that Aaron should be instead of a mouth, and Moses instead of God; that is, Moses was to dictate what Aaron should faithfully report, and to prescribe what he should obediently follow.

By this example, God bore witness that the gifts of the Spirit, as well as our vocations, are distributed by Him at His own good pleasure, and that no one excels either in honor or in gifts, except according to the measure of His free bounty.

But that the first-born is made subject to the younger and is only appointed to be his spokesman—when God might have accomplished by Aaron’s hand and labor what He instead chose to perform by Moses—from this, let us learn to reverently regard His judgments because they are incomprehensible to us and like a deep abyss.

The phrase To be instead of God means to lead, direct, or have the chief command; as the Chaldee Paraphrast⁵⁵ renders it, to be the chief or master. It is a very weak calumny of the Arians to abuse this and similar passages to refute the proofs of Christ’s divinity because there is a great difference between speaking of one as God simply and absolutely, and speaking of one as God with circumstantial additions.

For we know that the name of God is attributed to every ruler—improperly, indeed, yet not unreasonably. This occurs, for example, when the devil himself is called the god of this world, (2 Corinthians 4:4). But wherever mention is made of the true Deity, Scripture never profanes that sacred name.

⁵⁵ In the Targum of Onkelos, who has employed רב for the אלהים of the Hebrew. — W