The Priesthood is eternal. It has no beginning and no end; it was in existence before mortality and will be after mortality. Therefore, it was in the eternal state before mortality and will continue in the eternal state after mortality. Again, the foreknowledge of God is the basis for the preparation or delegation of God’s power to men (v. 17).
The calling that comes with the priesthood is holy because it comes from God, who is holy. Those who receive ordination to the priesthood, receive it from him who reigns on high and grants men his power. Therefore, it is the high priesthood and it is eternal, without beginning or end.
The order of the priesthood delegated to mortal men is the order of the Son. The Father has “committed [delegated] all his judgment [authority] unto the Son: That all men should honour the Son, even as they honour the Father” (John 5:22–23). Therefore, it is “after the order of the Son,” who is also eternal, without beginning or end, and has the attributes of God: grace, equity, and truth (Alma 13:9). The priesthood was originally called “The Holy Priesthood, after the Order of the Son of God” (D&C 107:3).
The ordination of the “many who were ordained” to be high priests was based upon faith, repentance, righteousness and works (v. 10). As men exercise the priesthood, it has a purifying effect upon them. They become sanctified [holy] and the Atonement of Christ takes away their sins (v. 11). In addition to the priesthood, they are given the Holy Ghost, which is also a sanctifying gift if they receive it. Because of their pure and spotless (divine) nature, they cannot look upon sin without abhorring that sin (v. 12). Nonetheless, as the Prophet Joseph Smith said: “I love you all; but I hate some of your deeds” (TPJS, 361). Sanctification is not limited to a few, but to all who will magnify the priesthood and be guided by the Holy Ghost. Alma refers to an exceeding great many who lived prior to his day and entered into the rest of the Lord (Alma 13:12). Undoubtedly there were an exceeding great many after the time of Alma, and in this dispensation, who have and will be sanctified.