At first when I began reading Alma 13, I thought that this was a random chapter that Mormon included of the teachings of Alma to Zeezrom and the people of Ammonihah. Random. Truthfully, though, there is nothing random about the Book of Mormon. If I find it random, that means I'm missing the point of why it is there. This is a beautiful chapter on the Melchizedek priesthood. Alma explains that the purpose of the priesthood is "that thereby the people might know in what manner to look forward to his Son for redemption." (Alma 13:2) Worthy Melchizedek Priesthood holders are commissioned to act in God's name for the salvation of man. They become a "type" of Christ. Their authority comes through ordination, but their POWER comes through obedience and worthiness. God's POWER, through your faith in HIM.
As a parent, sometimes it is difficult to relinquish control to a son/daughter. I really struggle with handing over my car keys to my teenage daughters. Whether they're safe drivers or not, I physically have an "uptight" feeling in my chest until they're home safe, and my undamaged car is back in the garage. Parents always worry about the safety of their children, other passengers, other drivers, pedestrians, or financial liability associated with driving a car. Realistically, though, I want my children to grow up being capable, responsible, well-informed, experienced, safe drivers. Someday, I'll be a grandmother and my daughters will be driving my grandchildren from place to place. I want all of them safe! I want my daughters to respect the POWER they control behind the wheel of a car. In order to do this, I must be willing to hand over my keys and let them practice driving. As they gain more confidence, experience and knowledge, they become capable drivers with control behind the wheel.
The Melchizedek Priesthood is God's POWER given to men to exercise according to their faith in Him. The period of time we spend here on earth is when we "practice" using this entrusted priesthood POWER. We do that by serving others, bringing others to Christ, sharing the gospel and guiding them to the temple. Through temple ordinances, men and women can receive the blessings of the Melchizedek priesthood and prepare to "enter God's rest". As we remain worthy, the Spirit sanctifies us through our service. The more we exercise this POWER, the more we develop a reverence for it. If we are to become like God, we must receive and exercise his priesthood or POWER as he exercises it.
Alma is teaching about the priesthood in preface to what is about to happen. The people in Ammonihah are practicing priestcraft, in contrast to the priesthood which Alma holds. One is of God, and the other of the devil. The people of Ammonihah are about to witness the POWER of God through the faith that Alma and Amulek have in Him (Alma 14). There will be no question where this POWER comes from. What a great chapter!