Speaking of the Savior, King David said:
The Lord hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek.Psalm 110:4
Commenting on this passage, the apostle Paul wrote the following cryptic description of Melchizedek:
Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually.Hebrews 7:3
And the prophet Alma used similar language when teaching the people in the city of Ammonihah about the priesthood:
This high priesthood being after the order of his Son, which order was from the foundation of the world; or in other words, being without beginning of days or end of years, being prepared from eternity to all eternity, according to his foreknowledge of all things…
Thus they become high priests forever.Alma 13:7, 9
Alma went on to affirm that Melchizedek “took upon him the high priesthood forever.” (Alma 13:14).
A priest is a person who is authorized to perform sacred rites in a church. How is it possible to be a priest forever?
The Gospel Topics section of churchofjesuschrist.org offers the following clarification:
The word priesthood has two meanings. First, priesthood is the power and authority of God. It has always existed and will continue to exist without end (see Alma 13:7–8; Doctrine and Covenants 84:17–18). Through the priesthood, God created and governs the heavens and the earth. Through this power, He exalts His obedient children, bringing to pass “the immortality and eternal life of man” (Moses 1:39; see also Doctrine and Covenants 84:35–38).
Second, in mortality, priesthood is the power and authority that God gives to man to act in all things necessary for the salvation of God’s children. The blessings of the priesthood are available to all who receive the gospel (“Priesthood Authority,” Handbook 2, Administering the Church).“Priesthood,” Gospel Topics
So priesthood is the power and authority to perform God’s work within a specific role in the church. But in a larger sense, priesthood is the eternal power and authority of God which He grants to His worthy children. Under the first definition, the authority is temporary, limited to our tenure in the role. Under the second, it is permanent, available to us as long as we remain faithful, even beyond the grave.
In an 1841 revelation received by Joseph Smith, we see the contrast between these two meanings of the word “priesthood.” Speaking of David Patten, an apostle who had been killed, the Lord said:
David Patten I have taken unto myself; behold, his priesthood no man taketh from him; but, verily I say unto you, another may be appointed unto the same calling.Doctrine and Covenants 124:130
Shortly after, the Lord made a similar statement about another church leader who had recently died:
Seymour Brunson I have taken unto myself; no man taketh his priesthood, but another may be appointed unto the same priesthood in his stead.Doctrine and Covenants 124:132
Today, I will remember the eternal nature of the priesthood. I will be grateful that God has entrusted His eternal power to me, and I will remember that He will share that power with me forever if I am faithful.