For it became him, for whom ( διὰ, with accusative) are all things, and through whom ( διὰ with genitive) are all things (i.e. God), in bringing many sons unto glory, to make the Captain of their salvation perfect through sufferings.
This refers to what was said in the preceding verse, of Christ having been crowned with glory on account of his suffering of death, and of his tasting death for all. That he should attain through human suffering even unto death to his own perfected state of glory, as being the Leader of human sons whom the one Father of all would bring to glory, was a design worthy of him for whom and through whom are all things—suitable to what we conceive of him and of his way of working.
The word ἔπρεπε is used in the same sense not infrequently in the LXX. It is probably used here with some view to "the offence of the cross," which might still linger in the minds of some of the Hebrew Christians.
In the argument that follows, supported still by reference to Old Testament anticipations, the writer not only meets possible objections lingering in the Hebrew mind, but also carries on and completes the view of the SON which it is his purpose to inculcate, leading up (as aforesaid) to the final position of his being the High Priest of humanity.