Only in Greek, it is shown this, that Abraham gave the best...the first fruits, to God, to Melchizedek.
Of commentators JFB and Barnes, Albert Barnes had it the clearest:
...The Greek word rendered here “spoils” - ἀκροθίνιον akrothinion - means literally, “the top of the heap,” from ἄκρον akron, “top,” and θίν thin, “heap.” The Greeks were accustomed, after a battle, to collect the spoils together, and throw them into a pile, and then, before they were distributed, to take off a portion from the top, and devote it to the gods...
Thus, Hebrews 7:4 is the only place of the whole Bible is this term ἀκροθίνιον used, aptly observed by the Chinese Union (上等之物) and NASB translation but not the NIV nor KJV.