Topical Guide: K
Keys of the Priesthood
Keys restored by Moses, Elias, and Elijah.
Tad R. Callister, "The Inevitable Apostasy", pp. 299-303
Discusses what the keys of the priesthood are and what happened to them during the Great Apostasy.
"The priesthood is always regulated by those who have the keys, and an ordinance must be authorized by the presiding authority who holds the proper keys and priesthood if the ordinance is to be recorded on the records of the Church."

"The keys of presidency and the authority to act in callings in the priesthood are received by setting apart." (As opposed to ordination.)

Women do not receive keys.

"The bishop is the president of the Aaronic Priesthood. He has the keys conferred upon him at the time of his ordination."

"All men who are ordained Apostles and sustained as members of the Quorum of the Twelve Apostles have all priesthood keys conferred upon them."

"The President of the Church is the only person on earth who has the right to exercise all the keys in their fulness."

"The power and authority of the higher, or Melchizedek Priesthood, is to hold the keys of all the spiritual blessings of the church."

"The power and authority of the lesser, or Aaronic Priesthood, is to hold the keys of the ministering of angels, ..."

"Keys are conferred upon a man when he is set apart to be a president, such as a president of a stake, of a quorum, or as a bishop. Counselors do not receive keys."

"There are keys of the priesthood. While the word key has other meanings, like keys of wisdom or keys of knowledge, the keys of the priesthood are the right to preside and direct the affairs of the Church within a jurisdiction. All priesthood keys are within The Church of Jesus Christ of Latter-day Saints, and no keys exist outside the Church on earth."
Killing Condoned or Commanded by God
Nephi kills Laban by command of the spirit.