Brigham Young was the first Mormon prophet to publicly teach blood atonement. In standard Christianity and in Mormonism today, the sacrifice that Christ made for humanity’s sins is enough for humanity to achieve forgiveness. The blood atonement doctrine stated that certain sins required the blood of the sinner to be shed for the sinner to obtain forgiveness.
Blood Atonement was first mentioned in an 1839 manuscript that said that the Lord had given the first Mormon prophet a revelation that Peter had hung Judas in an attempt to avenge his portrayal of Judas. Years later, after the Mormons had built their home in Utah and Salt Lake City, Brigham Young would announce the doctrine of blood atonement.
The sins which required the shedding of blood to achieve atonement were murder, lying, and, according to the Utah Light House Ministry, long time critics of the Church of Jesus Christ of Latter Day Saints, taking the name of the Lord in vain.
Brigham Young equated the willful murder of Mormons, particularly those who had left the church, to be showing love to them, but it is hard to tell how many Mormons were killed because of the introduction of the blood atonement doctrine.
Blood Atonement Falls Out of Favor
Blood atonement fell out of favor in Mormonism long after the death of Brigham Young and the traditional view of forgiveness that the rest of Christianity espouses won out. The 10th Prophet of the Mormon Church, Joseph Fielding Smith, would issue a statement that said there were some sins that the sacrifice of Christ could not atone for, but blood atonement not long survive as part of Mormon doctrine.
Blood Atonement today is just a historical anomaly espoused by some of the earlier and more controversial leaders of the Church of Jesus Christ of Latter Day Saints. Today, the idea that some sins require the death of the sinners is either written off as something that does not happen anymore or lies created by an anti-Mormon group.
Sources:
Journal Of Discourses