Doctrine & Covenants 84:17–18 reads as follows:

Which priesthood continueth in the church of God in all generations, and is without beginning of days or end of years. And the Lord confirmed a priesthood also upon Aaron and his seed, throughout all their generations, which priesthood also continueth and abideth forever with the priesthood which is after the holiest order of God. 

These verses affirm the everlasting nature and essential roles of both the Melchizedek and Aaronic Priesthoods in God’s plan and church organization. They affirm that the priesthood has always been present in the church whenever it has been organized. As scholars Stephen E. Robinson and H. Dean Garrett explain:

This allusion and the Joseph Smith Translation clear up a misunderstanding about Melchizedek from the text of Hebrews 7:3, in which Melchizedek is said to be “without father, without mother, without descent, having neither beginning of days, nor end of life.” The Joseph Smith Translation and Doctrine & Covenants 84 clarify that it is the priesthood of Melchizedek, not the man himself, that was so described. According to Joseph Smith, “The Priesthood is an everlasting principle, and existed with God from eternity, and will to eternity, without beginning of days or end of years. The keys have to be brought from heaven whenever the Gospel is sent.”¹⁹³

This underscores the Latter-day Saint teaching that the priesthood is really God’s power. He grants us keys to use it on earth and has done so in any generation that the Church has been organized.

Robinson and Garrett mention Hebrews 7. Critics have an objection to the notion that the priesthood continues in every dispensation in which the Church is organized that stems from their reading of Hebrews 7:24. That verse reads as follows:

but because Jesus lives forever, he has a permanent priesthood (NIV).

The term translated as “permanent” is aparábaton and some commentators before the turn of the 20th century believed that this meant Jesus’ priesthood was “non-transferrable.” Academic biblical research has disproved that notion, confirming that aparábatos simply means “permanent” and not “non-transferable.”¹⁹⁴

Latter-day Saints are blessed to have this knowledge of the Melchizedek. The Church has always been and always will be organized under the guiding umbrellas of the Melchizedek and Aaronic priesthoods. This understanding is unique and exclusive to those of the Latter Day Saints Movement.