The priesthood is the power to act in God's name. In the Mormon faith, all worthy males over the age of twelve can hold the priesthood, not just a select clergy or chosen few. However, there are offices in the Priesthood, and two divisions—the Aaronic Priesthood, and the Melchizedek Priesthood. Only Melchizedek Priesthood holders have the authority to give priesthood blessings through the laying on of hands, though priests, who hold the Aaronic Priesthood, can assist.
Anyone seeking divine counsel can receive a priesthood blessing. The power of the blessing to heal, comfort, and inform is manifested through the faith of the receiver and the Priesthood holder. Priesthood blessings are given on a variety of occasions, including the blessing of babies, confirming members of the church, healing the sick, and ordaining men to the priesthood. Priesthood blessings can be given during times of illness or injury, or when a person is seeking comfort from the Lord.
When a personal blessing is given, the priesthood holder seeks promptings from the Holy Ghost to know the needs of the individual and inspiration as to what to say in the blessing. On certain occasions, oil consecrated for the healing of the sick is used in the blessing. Two elders are needed in the case of using consecrated oil. One seals the blessing with a drop of oil placed on the head of the seeker, and the other pronounces a blessing through the promptings of the Lord. In order to give priesthood blessings, priesthood-holders must keep themselves worthy of this divine and sacred power. The purpose of a priesthood blessing is to provide healing, comfort, and counsel to the person seeking it.
It should be noted that though powerful and miraculous healings often occur when priesthood blessings are given, this is not always the case. Members of The Church of Jesus Christ of Latter-day Saints seek medical care when they are sick, and sometimes a priesthood blessing counsels the seeker to do just that. Sometimes a priesthood blessing is given to a person who is dying, and the promptings of the Holy Ghost are that the person should not be healed, but sent on his way with words of comfort.
Through priesthood blessings, the Lord is able to communicate through words with the seeker. His counsel can commend the seeker, help him with decisions, refer him to the scriptures, give him insights that can help with personal relationships and moral choices, help him resolve personal conflicts and overcome weaknesses, and better understand his trials and tribulations. Priesthood blessings are always revelatory and can be prophetic.
Access to priesthood blessings is one of the great rewards of membership in the Church— insight, healing, and comfort can be so profound, that it's difficult for the worthy member to imagine living life without that access. Understanding the purpose of priesthood blessings is to understand the nature of the true gospel—the charismatic gifts of the Spirit are again available to God's children, but they are bestowed in an organized, sacred, and peaceful manner. There is no aspect of showmanship, and no man or woman can claim healing or revelatory power on his or her own. The charismatic gifts are bestowed on God's children through proper authority, and they are to be used according to the dictates of God: "Behold, mine house is a house of order, saith the Lord God, and not a house of confusion"(Doctrine and Covenants 132:8).