Thomas S. Monson said this quote

“ I think one of the sweetest lessons taught by the Prophet, and yet one of the saddest, occurred close to the time of his death. He was required to leave his plan and vision of the Rocky Mountains and give himself up to face a court of supposed justice.These are his words: 'I am going like a lamb to the slaughter; but I am calm as a summer's morning; I have a conscience void of offense towards God, and towards all men' (D&C 135:4). That statement of the Prophet teaches us obedience to law and the importance of having a clear conscience toward God and toward our fellowmen. The Prophet Joseph Smith taught these principles--by example.There was to be one great final lesson before his mortal life ended. He was incarcerated in Carthage Jail with his brother Hyrum, with John Taylor, and with Willard Richards. The angry mob stormed the jail; they came up the stairway, blasphemous in their cursing, heavily armed, and began to fire at will. Hyrum was hit and died. John Taylor took several balls of fire within his bosom. The Prophet Joseph, with his pistol in hand, was attempting to defend his life and that of his brethren, and yet he could tell from the pounding on the door that this mob would storm that door and would kill John Taylor and Willard Richards in an attempt to kill him.And so his last great act here upon the earth was to leave the door and lead Willard Richards to safety, throw the gun on the floor, and go to the window, that they might see him, that the attention of this ruthless mob might be focused upon him rather than the others. Joseph Smith gave his life. Willard Richards was spared, and John Taylor recovered from his wounds.'Greater love hath no man than this, that a man lay down his life for his friends' (John 15:13). The Prophet Joseph Smith taught us love--by example. ”