Hebrews 7:4

Now consider how great this man was
Melchizedek, of whom so many great and wonderful things are said in the preceding verses: and as follows,

unto whom the patriarch Abraham gave the tenth of the spoils;
of Abraham's giving tithes to him, (See Gill on Hebrews 7:2) and Melchizedek's greatness is aggravated, not only from this act of Abraham's, but from Abraham's being a "patriarch", who did it; he was the patriarch of patriarchs, as the sons of Jacob are called, ( Acts 7:8 Acts 7:9 ) he is the patriarch of the whole Jewish nation, and of many nations, and of all believers, the friend of God, and heir of the world; how great then must Melchizedek be, to whom he paid tithes? and how much greater must Christ, the antitype of Melchizedek, be?