"For this Melchizedek, king of Salem, priest of the Most High God, met Abraham returning from the slaughter of the kings and blessed him, 2 and to him Abraham apportioned a tenth part of everything. He is first, by translation of his name, king of righteousness, and then he is also king of Salem, that is, king of peace. 3 He is without father or mother or genealogy, having neither beginning of days nor end of life, but resembling the Son of God he continues a priest forever.
4 See how great this man was to whom Abraham the patriarch gave a tenth of the spoils! 5 And those descendants of Levi who receive the priestly office have a commandment in the law to take tithes from the people, that is, from their brothers, though these also are descended from Abraham. 6 But this man who does not have his descent from them received tithes from Abraham and blessed him who had the promises. 7 It is beyond dispute that the inferior is blessed by the superior. 8 In the one case tithes are received by mortal men, but in the other case, by one of whom it is testified that he lives. 9 One might even say that Levi himself, who receives tithes, paid tithes through Abraham, 10 for he was still in the loins of his ancestor when Melchizedek met him."
Hebrews 7:1-10
The second point the Apostle makes is that this mysterious priest received tithes from Abraham, thus showing that Abraham, and in him his descendant, the sons of Levi, recognized his superiority over them. Anyone who could bless Abraham who had the promises must be great indeed, for it is always the less who is blessed by the better (7). All this may sound rather an ingenious and unusual way of reasoning, but it is not by any means a fanciful one, but imbedded in the structure of the Scriptures. For the phrase 'after the order of Melchizedek' is a quotation from Psalm 110 - an acknowledged Messianic Psalm, and one which is quoted in the New Testament almost more than any other Psalm. Without doubt it is a prophecy and prediction of the coming reign of the Messiah, and as such - and here is the significance of its being quoted here - stands as a confession and acknowledgement that the sacrificial system of the old economy was unable to deal with the problem of sin. It was ineffectual, because it had no inherent worth, Its sacrifices were but shadows cast upon the course of history by the Lamb slain from the foundation of the world and thus pointed beyond themselves to the One Who was to come, Whose Priesthood would really be effectual and sufficient for the needs of men. And this the Apostle now proceeds to deal with in the rest of the chapter,