The LDS Church teaches that the priesthood is the power and authority of God to act on His behalf. All worthy male members enter the priesthood. Only they can properly administer the ordinances; thus, the LDS Church does not recognize Christian baptism. They believe the priesthood also gives them power to receive revelations. There are two priesthoods: the Aaronic and the Melchizedek.
The Aaronic priesthood serves as the entry point into the priesthood for boys twelve and older and adult male converts. It is responsible for the church’s temporal affairs.
The Melchizedek priesthood is for all worthy adult male members. "Through the authority of the Melchizedek Priesthood, Church leaders guide the Church and direct the preaching of the gospel throughout the world. This greater priesthood was given to Adam and has been on the earth whenever the Lord has revealed His gospel. It was taken from the earth during the Great Apostasy, but it was restored in 1829, when the Apostles Peter, James, and John conferred it upon Joseph Smith and Oliver Cowdery." (True to the Faith, p. 101)
Biblical Christianity teaches that every male and female believer is a member of the holy and royal priesthood (1 Peter 2:5-9). They are holy and righteous in God's eyes because of the perfect life and sacrificial death of Jesus Christ.