In these verses Alma establishes Melchizedek as a type for Christ, noting the following parallels: First, like Christ, he was a king. The very name of this great high priest—Melchizedek, “king of righteousness” or, perhaps more correctly, “my king is righteousness”-affirms and testifies of the goodness and power of the coming Messiah.
Righteousness is also a name-title of Christ (see Moses 7:45). As Melchizedek ruled his kingdom in righteousness, so Christ will eventually rule and reign upon this earth, doing so with the unchanging scepter of righteousness and truth, possessing an everlasting dominion without compulsory means (see D&C 121:46).