Melchizedek is only mentioned one time in the Book of Mormon. Why is it here [in Alma 13:14-18]? It is interesting that Alma was just preaching in the city of Melek, and has come to the people of Ammonihah, which were probably of similar Mulekite descent. According to Joseph McConkie, "of the Old Testament kings none was greater than Melchizedek." An earlier chapter considered him as a type for Christ; here we refer briefly to the significance of his name. The root for the forepart of his name, Melch (Melek), means "king" or "royal". [Joseph McConkie, Gospel Symbolism, p. 188]
Note* Could these Mulekite people in the land of Ammonihah have been of royal descent or more pure descendants of the tribe of Judah, and thus felt superior to everyone else? [Alan C. Miner, Personal Notes]
“It Was This Same Melchizedek to Whom Abraham Paid Tithes”
Why was Alma not only using the example of Melchizedek in preaching to the people of Ammonihah, but pointing out that "Abraham paid tithes" to him (Alma 13:15)? Apparently, many of the people of Ammonihah were Mulekites, of Jewish extraction (see the commentary on Alma 8:20). The ultimate priesthood authority for the Jews was Abraham.
Robert Millet addresses the question, "And what of the relationship of Melchizedek to Abraham?" Alma mentions simply that Abraham paid tithing to him. An old tradition among the Jews states that "Melchizedek, the king of righteousness, priest of God Most High, and king of Jerusalem, came forth to meet [Abraham]," as Abraham was returning from the war "with bread and wine. And this high priest instructed Abraham in the laws of the priesthood and in the Torah" (Ginzberg 1:233; emphasis added). . . .
On 27 August 1843, Joseph Smith offered prophetic commentary on the seventh chapter of Hebrews, Paul's discussion of the place and power of the Melchizedek Priesthood. According to James Burgess, the Prophet said:
Paul is here treating three different priesthoods, namely, the priesthood of Aaron, Abraham, and Melchizedek. Abraham's priesthood was of greater power than Levi's, and Melchizedek's was of greater power than that of Abraham. . . . I ask: was there any sealing power attending this [Levitical] Priesthood that would admit a man into the presence of God? Oh no, but Abraham's was a more exalted power or priesthood. He could talk and walk with God. And yet consider how great this man [Melchizedek] was when even this patriarch Abraham gave a tenth part of all his spoils and then received a blessing under the hands of Melchizedek--even the last law or a fulness of the law or priesthood, which constituted him a king and priest after the order of Melchizedek or an endless life. (Words of Joseph Smith 245-46, spelling and punctuation corrected; emphasis added.) [Robert L. Millet, "The Holy Order of God," in The Book of Mormon: Alma, The Testimony of The Word, pp. 81-82]
Note* Apparently Alma emphasized the point that Abraham not only received the fulness of the priesthood under the hands of another man--Melchizedek, but that the order of the priesthood of Melchizedek was a "type" of the order of the Son of God (Alma 13:16). [Alan C. Miner, Personal Notes]
Alma 13:15 It was this same Melchizedek to whom Abraham paid tithes ([Illustration]): Untitled. Artist: Clark Kelley Price. [Dennis A. Wright, " 'None Were Greater,' A Restoration View of Melchizedek," in The Ensign, February 1998, p. 32]
Alma 13:15 It was this same Melchizedek [a high priest and king of Salem] to whom Abraham paid tithes ([Illustration]): Melchizedek Ordaining Abraham. Melchizedek, the king of Salem, was a mighty and faithful high priest. Melchizedek was Abraham's priesthood leader and is shown here blessing Abraham. Artist: Gary Kapp. [Thomas R. Valletta ed., The Book of Mormon for Latter-day Saint Families, 1999, p. 303]