Hebrews 5:9

9.And being made perfect, or sanctified, etc. Here is the ultimate or the remoter end, as they call it, why it was necessary for Christ to suffer: it was that he might thus become initiated into his priesthood, as though the Apostle had said that the enduring of the cross and death were to Christ a solemn kind of consecration, by which he intimates that all his sufferings had a regard to our salvation. It hence follows, that they are so far from being prejudicial to his dignity that they are on the contrary his glory; for if salvation be highly esteemed by us, how honorably ought we to think of its cause or author? For he speaks not here of Christ only as an example, but he ascends higher, even that he by his obedience has blotted out our transgressions. He became then the cause of salvation, because he obtained righteousness for us before God, having removed the disobedience of Adam by an act of an opposite kind, even obedience.

Sanctified suits the passage better than “made perfect.” The Greek word τελειωθεὶς means both; but as he speaks here of the priesthood, he fitly and suitably mentions sanctification. And so Christ himself speaks in another place, “For their sakes I sanctify myself.” (John 17:19.) It hence appears that this is to be properly applied to his human nature, in which he performed the office of a priest, and in which he also suffered. (90)

To all them that obey him. If then we desire that Christ’s obedience should be profitable to us, we must imitate him; for the Apostle means that its benefit shall come to none but to those who obey. But by saying this he recommends faith to us; for he becomes not ours, nor his blessings, except as far as we receive them and him by faith. He seems at the same time to have adopted a universal term, all, for this end, that he might show that no one is precluded from salvation who is but teachable and becomes obedient to the Gospel of Christ.