A Bible study on the Melchizedek priesthood:
Q: What requirements are necessary for one to belong to the Aaronic priesthood?
A: One must be on earth (Hebrews 8:4-5), and descend genetically from the tribe of Levi (Hebrews 7:14; Numbers 18:7).
Q: What requirements are ncessary in order for one to belong to the Melchizedek priesthood?
A: One must have within himself "the power of an endless life" (Hebrews 7:16), and not be present on earth during the time of one's priestly service (Hebrews 8:4).
Q: What is different about the current Melchizedek priesthood?
A: An individual other than a descendent of the tribe of Levi may serve as high priest (Hebrews 7:14, 17, 21).
Q: Does "priest" in Hebrews seven actually mean "priesthood?"
A: The LDS missionary has been taught that this is so, but it is not. These are two separate words. "Priest," a third declension, masculine, singular noun, occurs in verses 1, 3, 11, 15, 17, 21, 26. The same word, but in the plural form appears and is translated as such in verses 21, 23, 27, 28. The word "priesthood" is another, different word and occurs in verses 5, 11, 12, 14, 24 and is translated as such. The words are distinct from each other. The singular references to "priest" can not be taken legitimately to mean "priesthood" in a general sense. They mean rather a single individual priest.
Q: There are two different "orders" of priesthood: the Aaronic and the Melchizedek. Does the fact that there are two orders necessarily mean or imply that each order would have numerous priests at the same time?
A: No. The many priests of the Aaronic order "were not suffered to continue by reason of death." Jesus, however, now as the Melchizedek Priest, is made such according to the fact that He has endless life (Hebrews 7:17). That is, having within oneself' "the power of an endless life" is a requirement for one to serve in the order of the Melchizedek priesthood.
Q: But the original Melchizedek was a mere man, not God and not possessing in himself the power of an endless life.
A: Correct. However, consider this. His priesthood is never called a "high priesthood." The time during which he served on earth as "priest of the most high God" was many centuries before heaven instituted the Levitical priesthood. The priesthood was changed after Christ had died from the Levitical to the Melchizedek (Hebrews 7:12). The law of the priesthood was also changed so that one not of the tribe of Levi could serve as "high priest" (Hebrews 7:12-16). Finally, do not miss the point that just as the Levitical priesthood on earth was a type or shadow or symbol of the true priesthood of Christ that would come in heaven, so the original service of the individual named Melchizedek on earth was a type or shadow or symbol of the true priesthood of Christ that would come in heaven. Hebrews 7:15 says that it is "after the similitude of Melchizedek that "there ariseth another priest."
Q: Why could Jesus not be a priest while on earth (Hebrews 8:4)?
A: Because the Levitical priests served only "unto the example and shadow of heavenly things" (Hebrews 8:5). But Jesus serves today in "a more excellent ministry" (Hebrews 8:6), "For Christ is not entered into the holy places made with hands, which are figures of the true; but into heaven itself, now to appear in the presence of God for us" (Hebrews 9:24). Jesus is the antitype , the true, to which the types, the earthly priesthood in all its shadows pointed. Since He is the true, were He to serve on earth in the shadow priesthood He would blur the careful distinction between the symbol and the reality.
Because the seventh chapter of Hebrews has been "restored" through Joseph Smith's specially revealed translation, and argues with itself, while the same chapter as it stands in our standard Bibles harmonizes fully with itself, we are justified in accepting the regular translation and rejecting the JST. Nor can anyone say that the JST is superior, because it argues with itself (proposing an earthly priesthood of mortal, Melchizedek priests) while Jesus who has not yet vacated the priesthood cannot have been replaced by another high priest.