John Doyle Lee recalls an oath of vengeance taken by Saints to avenge the blood of Joseph and Hyrum Smith.
John Doyle Lee, Mormonism Unveiled; or, The Life and Confessions of the late Mormon bishop, John D. Lee (St. Louis: Bryan, Brand & Company 1877), 160
I was in Brigham Young's office about this time. His brother Joseph, and quite a number of others were present, when Brigham raised his hand and said, "I swear by the eternal Heavens that I have unsheathed my sword, and I will never return it until the blood of the Prophet Joseph and Hyrum, and those who were slain in Missouri, is avenged. This whole nation is guilty of shedding their blood, by assenting to the dead, and holding its peace." "now," said he," betray me, any of you who dare to do so!" Furthermore, every one who had passed through their endowments, in the Temple, were placed under the most sacred obligations to avenge the blood of the Prophet, whenever an opportunity offered, and to teach their children to do the same, thus making the entire Mormon people sworn and avowed enemies of the American nation.