Under the Banner of Heaven by Jon Krakauer, 2003, Excerpts
In May 1845, nine men were indicted for the murders of Joseph and Hyrum Smith, seven of whom were brought to trial in Carthage. On May 30, to nobody’s astonishment, all nine defendants were found not guilty.
Brigham instructed church authorities to issue a formal “Oath of Vengeance,” which was immediately made part of the temple endowment ceremony, one of the church’s most sacred rituals. The oath required Mormons to pledge, “I will pray, and never cease to pray, and never cease to importune high heaven to avenge the blood of the Prophets on this nation, and I will teach this to my children, and my children’s children unto the third and fourth generations.” This solemn vow to take vengeance was recited by every Latter-day Saint who participated in the standard temple ritual until it was removed from the endowment ceremony in 1927, after the oath was leaked to the non-Mormon press, sparking an outcry from politicians and the Gentile public that it was treasonous.