Continuing forward, roughly from whom he appointed heir of all things, and through whom he made the universe…

Having declared that the Son is the immediate revealer of the gospel, he proceeds in his argument by declaring the glory and excellency of the Son, both what he had before he took the office of mediator and what he received after he did so.

Two things are assigned to the Son
1. That he was appointed heir of all
2. That by him the worlds were made
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First, whom he appointed heir of all things

1. whom, meaning the Son

As God, the Son has a natural dominion over all things, as God rules over them all, so the Son rules over them as well. This inheritance comes to him, therefore, not as he is God, but as he is God and man in one person. The inheritance is for Jesus Christ, in other words, the Son as he is in his office of mediator. This difference is expressed by Owen as follows: Nothing can be added unto him as God, but there may be to him who is God, in respect of his condescension to discharge an office in another nature which he did assume. The distinction may seem pedantic, but such preciseness is important in order to defend the person of Christ from those who would use this Scripture to attack his divinity.

2. heir, meaning not one who receives an inheritance upon the death of another, for the Father does not die. The right sense of it is the lawful possessor of some property received by grant from another. The word is intended to convey three things

a. Title, dominion, lordship—The heir is lord of all to which he is heir.
b. Possession—Christ actually comes to possess those things of which he is heir
c. Grant—That both the title and the possession comes by a grant from the one who owns them

3. of all things—This is the objects of his inheritance, and since it is in the neuter gender, it denotes all things absolutely. Defending this interpretation:
a. Cross-reference I Cor xv.27, where it is also used in this sense
b. This suits the course of his argument, showing that since the author of the gospel is the heir of all things, he had a right to change the rites and ordinances of worship (which is a main theme of much of the argument to come esp. ch. 7-10)
c. The words which follow, by whom he made the universe, line up with this interpretation, that he who made all things also is heir of them all
d. This interpretation lines up with the promise made to Abraham, that he should be heir of the world.
e. The origin and reason for this inheritance will also show us its scope, for this, see the aside below.

4. appointed—the way by which Christ came to be this heir, namely that God appointed him to it. This is God’s act by which he committed all power over all things in heaven and earth to him. This power was to be exercised towards the ends of his mediation, that is to, gather up the elect. This is seen in his resurrection, ascension, and sitting at the right hand of God.