The Doctrine and Covenants explains that the sin of murder cannot be forgiven, he that kills shall not have forgiveness in this world, nor in the world to come (DC 42:18,79). However, the Book of Mormon leaves some hope, saying, it is not easy for him to obtain forgiveness. The disparity occurs because of differences in the definitions of murder. The D & C definition refers to premeditated murder, like the sin that king David committed in the case of Uriah (DC 132:39). The Book of Mormon definition of murder includes those who have killed during military campaigns. After their conversion, the Anti-Nephi-Lehies considered their military killings murder because the Nephites killed were innocent. Certainly, this sort of killing is different than premeditated murder. Apparently, the Lord forgave these righteous Lamanites after they had repented (Alma 24:11).
Bruce R. McConkie
"Murder, the unlawful killing of a human being with malice aforethought or under such circumstances of criminality that the malice is presumed, ‘is a sin unto death’ (1 John 5:16-17), a sin for which there is ‘no forgiveness’ (D. & C. 42:79), meaning that a murderer can never gain salvation. ’No murderer hath eternal life abiding in him.’ (1 John 3:15.) He cannot join the Church by baptism; he is outside the pale of redeeming grace.
"The call to repentance and baptism which includes murderers (3 Ne. 30) has reference to those who took life while engaged in unrighteous wars, as did the Lamanites, because they were compelled to do so, and not because they in their hearts sought the blood of their fellow men…
“Murderers are forgiven eventually but only in the sense that all sins are forgiven except the sin against the Holy Ghost; they are not forgiven in the sense that celestial salvation is made available to them. (Matt. 12:31-32; Teachings, p. 356-357.) After they have paid the full penalty for their crime, they shall go on to a telestial inheritance. (Rev. 22:15.)” (Mormon Doctrine, p. 520)
“Whosoever Murdereth, It Is Not Easy for Him to Obtain Forgiveness”
The Doctrine and Covenants explains that the sin of murder cannot be forgiven, he that kills shall not have forgiveness in this world, nor in the world to come (DC 42:18,79). However, the Book of Mormon leaves some hope, saying, it is not easy for him to obtain forgiveness. The disparity occurs because of differences in the definitions of murder. The D & C definition refers to premeditated murder, like the sin that king David committed in the case of Uriah (DC 132:39). The Book of Mormon definition of murder includes those who have killed during military campaigns. After their conversion, the Anti-Nephi-Lehies considered their military killings murder because the Nephites killed were innocent. Certainly, this sort of killing is different than premeditated murder. Apparently, the Lord forgave these righteous Lamanites after they had repented (Alma 24:11).
Bruce R. McConkie
"Murder, the unlawful killing of a human being with malice aforethought or under such circumstances of criminality that the malice is presumed, ‘is a sin unto death’ (1 John 5:16-17), a sin for which there is ‘no forgiveness’ (D. & C. 42:79), meaning that a murderer can never gain salvation. ’No murderer hath eternal life abiding in him.’ (1 John 3:15.) He cannot join the Church by baptism; he is outside the pale of redeeming grace.
"The call to repentance and baptism which includes murderers (3 Ne. 30) has reference to those who took life while engaged in unrighteous wars, as did the Lamanites, because they were compelled to do so, and not because they in their hearts sought the blood of their fellow men…
“Murderers are forgiven eventually but only in the sense that all sins are forgiven except the sin against the Holy Ghost; they are not forgiven in the sense that celestial salvation is made available to them. (Matt. 12:31-32; Teachings, p. 356-357.) After they have paid the full penalty for their crime, they shall go on to a telestial inheritance. (Rev. 22:15.)” (Mormon Doctrine, p. 520)