According to John Tvedtnes, the Hebraisms in the Book of Mormon help persuade us that it is authentic … Alma, in speaking of Melchizedek, notes that “he was the king of Salem; and he did reign under his father” (Alma 13:18). This may reflect the normal biblical Hebrew use of the preposition under for the meaning instead of. The same preposition is rendered instead of in some passages of the King James Bible. For example, after King Amaziah had been murdered, “all the people of Judah took Azariah … and made him king instead of his father Amaziah” (2 Kings 14:21). [John A. Tvedtnes, “The Hebrew Background of the Book of Mormon,” in Rediscovering the Book of Mormon, F.A.R.M.S., pp. 90-91]
“He Did Reign Under His Father”
In Alma 13:18, it says that Melchizedek “did reign under his father.” We are told that Melchizedek received the priesthood through the lineage of his fathers (plural) even till Noah (D&C 84:14). It would appear to be that from Melchizedek to Noah was a lineage of fathers (plural), or several generations. But who was Melchizedek’s father?
According to Richard Anthony, as Adam ordained Seth, so it would seem that Noah, acting like Adam, would ordain his sons. Thus, although we are not told in the scriptures who ordained Shem, we would conclude that it must have been Noah. In the same manner, the scriptures are likewise silent about the ordinations of Shem’s son and grandson, Arphaxed and Salah; but interestingly the Bible, in Genesis, names Arphaxed as the third born, and Salah as his (Arphaxed’s) firstborn. It is also very interesting that Luke recorded the chosen line through Arphaxed (the third born) and Salah to Heber, or Eber.
Concerning this deletion of the firstborn, the prophet Joseph gives us information. According to Genesis 10:12 (JST), “Shem was the father of Eber, and even to him were children born.” Verse 13 names Eber as the firstborn son of Shem. So how can this be? How can Eber be a son of Salah in the Bible and a son of Shem in the JST? It is Anthony’s opinion that the prophet Joseph made this seemingly insignificant change in a recitation of genealogy for a reason, and that reason has to do with the father-firstborn relationship. Shem outlived both Arphaxed (his son) and Salah (his grandson). For some reason, Heber (Eber) was made a “son” to his great-grandfather Shem, and was listed by Joseph Smith as his firstborn. Again it is Anthony’s opinion that Shem bestowed upon Eber this right, or birthright, or firstborn priesthood. In other words, generations were skipped, or links of the chain were bypassed to link up with a righteous heir. Thus this birthright went to Heber. It may be that Shem adopted Heber in much the same fashion that Jacob adopted his grandsons Ephraim and Manasseh to be his firstborn. For whatever reason, Anthony believes that Eber or Heber became the firstborn son of Shem, and reigned in that position under his father Shem.
This Heber was known as the First Hebrew (Harper’s Bible Dictionary, p. 378). If Heber was Melchizedek, the great high priest, and Abraham went to him and became his firstborn son through adoption, then this would explain why Abraham is known as the first Hebrew, or the firstborn son of Heber (Bible Dictionary). It would also explain why the descendants of Abraham, who hold the Melchizedek priesthood to bless all mankind, are known as the Hebrew children, or in other words, the Melchizedek children, or the firstborn children, or the children of the firstborn. [Richard D. Anthony, Isaiah & Joseph, pp. 28-29, unpublished]
Melchizedek Was Called the Prince of Peace for He Was the King of Salem and He Did Reign Under His Father
According to Cleon Skousen, Melchizedek was a contemporary of the great patriarch, Abraham. Abraham was ten generations down from Noah and lived approximately 2022 B.C. to 1847 B.C., so this gives us some estimate of Melchizedek’s time in history.
Melchizedek was somewhat older than Abraham and had such an illustrious political and prophetic career that when Abraham was still a youth he sought the Holy Priesthood from Melchizedek and longed to be called a “prince of peace” just like Melchizedek (Abraham 1:2 plus D&C. 84:14).
Melchizedek came from a royal family which had carved out a mountain kingdom in the very heart of the land of Canaan. This land was named after the eldest son of Ham and therefore its original inhabitants must have been largely Hamitic. Nevertheless, the fathers of Melchizedek had brought the descendants of Shem into this region and established a capital at Salem. Today we call the same area Jerusalem. Salem means “peace.” The Jeru is considered by many authorities to have started out as Uru, having come through an Assyrian word meaning city. (See Hastings’ Dictionary of the Bible, Vol. 3, p. 335.) Jerusalem would therefore mean, “City of Salem,” or City of Peace.“ … While there are other opinions, the Bible calls Jerusalem simply ”Salem“ in Psalms 76:2, and around 1,400 B.C., one of the rulers of this city called it merely ”Salem“ in writing to the Pharaoh of Egypt. (This is contained in the Tel el-Amarna collection quoted by Hastings, Vol. 2, p. 284). Ancient Jewish writings have always identified Melchizedek’s ”Salem" mentioned in Genesis 14:18 as being identical with the modern site of Jeru-salem (Ibid.).
Therefore, Melchizedek apparently grew up on the same sacred Mount Zion or Mount Moriah where Jesus Christ would conclude his earthly ministry some 2,000 years later… .
When Melchizedek became the ruler of the people of Salem he is said to have reigned “under his father” (Alma 13:18). This would mean either that his father ruled over a larger domain of which Salem was a part, or it could mean that he received his kingdom as a successor to his father.
In any event, there is one thing the scripture makes very clear: Melchizedek came to power at a time when the people of his city-kingdom were abominably wicked, but through his preaching and their repentance, peace was established (Alma 13:17-18). [W. Cleon Skousen, Treasures from the Book of Mormon, Vol. 2, pp. 2302-2303]
Note* Thus we see that Melchizedek was a type of Christ, who ruled over a people who had “all gone astray, they were full of all manner of wickedness” (Alma 13:17). By preaching repentance, he established Jerusalem as a place of peace where he “reigned under his father.” The Messiah of the Jews was not foreseen as coming to power in this manner. [Alan C. Miner, Personal Notes]