Heavenly Father gives a portion of His power and authority to worthy male members of the Church. This delegated authority is called the priesthood. Those who hold the priesthood are authorized to act in the Lord’s name in leading His Church, teaching the gospel, blessing the sick, and performing the sacred ordinances necessary for salvation.
The priesthood must be used worthily because, as the Lord revealed to Joseph Smith, “the rights of the priesthood are inseparably connected with the powers of heaven, and … the powers of heaven cannot be controlled nor handled only upon the principles of righteousness” (D&C 121:36). Thus, there is a difference between the authority and the power of the priesthood. “Priesthood authority, which is the authorization to act in God’s name, … is given by the laying on of hands. The power of the priesthood comes only when those who exercise it are worthy and acting in accordance with God’s will.”1
Because the priesthood is God’s power, He sets the standards of worthiness for its use and reveals those standards to His prophets and apostles. Priesthood holders become worthy by repenting of their sins and living in harmony with the gospel and commandments of Jesus Christ. The companionship of the Holy Ghost in their lives can help them know of their worthiness.
Priesthood holders gain power in the priesthood through faith and obedience:
Treat your wife, children, and others kindly.
Take the sacrament worthily.
Worship in the temple.
Serve faithfully in your calling.
Exercise the priesthood when called upon.