Premeditated murder is a “sin unto death” (1 John 5:16-17), meaning one for which there is“ no forgiveness” (D&C 42:79). “No murderer hath eternal life abiding in him,” John taught (1 John 3:15).
“A murderer,” Joseph Smith explained, is “one that sheds innocent blood, [and] cannot have forgiveness” (Teachings, p. 3:39). “Thou shalt not kill,” a modern revelation declares, “but he that killeth shall die” (D&C 42:19; cf. Alma 1:18; Genesis 9:6; Numbers 35:16; Deuteronomy 19:11-12).
“Murder is thus a sin unto death,” wrote Elder Bruce R. McConkie, “at least concerning members of the Church, to whom this revelation [D&C 42], which is entitled ’the law of the Church, ’ was addressed. We do know that there are murders committed by Gentiles for which they at least can repent, be baptized, and receive a remission of their sins. (See 3 Nephi 30:1-2.)” (New Witness, p. 231.)