Hebrews 5:6

He. That is, God, the speaker in v. 5.

Thou art a priest. A citation from Ps. 110:4, here quoted as evidence that God had appointed His Son to priestly office. The priesthood of Christ is fully discussed in subsequent chapters (Heb. 7-10).

For ever. In contrast with earthly high priests, who because of death held office for limited periods.

Order. Gr. taxis, “fixed succession,” “order,” “position,” “nature,” “quality,” “post,” “rank.” Here the definitions “fixed succession” or “order” do not appear suitable, for Melchisedec had no line of successors. Preferable are definitions like “quality” or “nature,” “manner.” The passage may be rendered, “according to the nature of Melchisedec.” In Ps. 110:4 the Hebrew word for “order” is dibrah, which means “manner.” This supports the idea that succession is not the point of comparison here intended.

Melchisedec. A transliteration of the Gr. Melchisedek, which in turn is from the Heb. Malki-sedeq. The spelling “Melchizedek” (Gen. 14:18) is a transliteration of the Hebrew. For the identity of Melchisedec see on Heb. 7:2.