That Abram, and not Melchizedek, was the tithepayer is clearly stated in Heb. 7:4. Giving the tenth of the booty taken from the enemy was an acknowledgment of the divine priesthood of Melchizedek, and proves that Abram was well acquainted with the sacred institution of tithe paying.

 This is the first mention of tithing, repeatedly recognized throughout both the OT and the NT as a divine requirement (see Gen. 28:22; Lev. 27:30–33; Num. 18:21–28; Neh. 13:12; Matt. 23:23; Heb. 7:8). That Abram paid tithe shows clearly that this institution was not later, temporary expedient to provide for the sacrificial services, but that it was a divinely instituted practice from the earliest times. By returning to God one tenth of his income the believer recognizes God’s ownership over all his property. Abram, of whom God testified that he had kept His commandments, statutes, and laws (Gen. 26:5), performed all his religious duties conscientiously. One of them was to return to God a tenth of his increase. In this act the father of the faithful set an example for all those who desire to serve God and share in the divine blessing. As in days of old, God’s promises for faithfulness in tithe paying are still valid (see Mal. 3:10). God is still ready to fulfill His promises and richly bless those who, like Abram, return to him a faithful tithe of their increase.