A.T. Robertson Commentary Hebrews 8:1

"Now in the things which we are saying the chief point [is this]: We have such a high priest, who sat down on the right hand of the throne of the Majesty in the heavens," — Hebrews 8:1 (ASV)

In the things which we are saying (επ τοις λεγομενοις). Locative case of the articular present passive participle of λεγω after επ as in Lu 5:5; Hebrews 11:4, "in the matter of the things being discussed."

The chief point (κεφαλαιον). Neuter singular of the adjective κεφαλαιος (from κεφαλη, head), belonging to the head. Vulgate capitulum, nominative absolute in old and common sense, the main matter (even so without the article as in Thucydides), "the pith" (Coverdale), common in the papyri as in Greek literature. The word also occurs in the sense of the sum total or a sum of money (Acts 22:28) as in Plutarch, Josephus, and also in the papyri (Moulton and Milligan's Vocabulary).

Such an high priest (τοιουτον αρχιερεα). As the one described in chapters 4:16-7:28 and in particular 7:26 (τοιουτος) 7:27,28. But the discussion of the priestly work of Jesus continues through 12:3. Τοιουτος is both retrospective and prospective. Here we have a summary of the five points of superiority of Jesus as high priest (8:1-6). He is himself a better priest than Aaron (τοιουτος in 8:1 such as shown in 4:16-7:28); he works in a better sanctuary (8:2,5); he offers a better sacrifice (8:3f.); he is mediator of a better covenant (8:6); his work rests on better promises (8:6); hence he has obtained a better ministry as a whole (8:6). In this resume (κεφελαιον) the author gives the pith (κεφαλαιον) of his argument, curiously enough with both senses of κεφαλαιον (pith, summary) pertinent. He will discuss the four points remaining thus: (1) the better covenant, 8:7-13. (2) The better sanctuary, 9:1-12. (3) The better sacrifice, 9:13-10:18. (4) The better promises, 10:19-12:3. One point (the better high priest, like Melchizedek) has already been discussed (4:16-7:28).

Sat down (εκαθισεν). Repetition of 1:3 with του θρονου (the throne) added. This phrase prepares the way for the next point.