Although Nauvoo was a sickly place, the industry of the Saints was attended with the blessings of divine Providence, and the city grew with magic speed. A temple was soon commenced. A charter was obtained from the State Legislature to establish a university, and prosperity almost unparalleled characterized the labors of the people. However, the combination of political intrigue and religious bigotry on the part of religious professors, coupled with transgressing apostates, soon conspired to spread death and destruction among the Saints. In Missouri, at Haun's mill and elsewhere, many had been shot down in cold blood, property was burned, and the whole people exiled from the state.

In Illinois further trouble was inaugurated by Missourians. They sought on one occasion to kidnap the Prophet, but failed. Fabricated charges were made against the Prophet. He was tried as before, and every time acquitted. When his last trial was being conducted, the mob (like the rabble in the halls of Pilate) said that if the law could not touch him, powder and lead should. Their nefarious purposes were permitted to be carried out, and on June 27th, 1844, Joseph and Hyrum, while under the pledged protection of Gov. Ford, were assassinated by a howling mob in Carthage jail, Hancock county, Illinois. Previous to his martyrdom, the Prophet Joseph had received more than one hundred revelations, had been instrumental in organizing the Church in its fullness, and bestowing the keys of the kingdom of God upon the Twelve Apostles. To Nauvoo were gathered thousands of people from the several states, Canada and Great Britain. At the time of the Prophet's martyrdom the Twelve were abroad on missions, with the exception of Elders John Taylor and Willard Richards, who were with the Prophet and Patriarch at the time of the martyrdom, Elder Taylor himself being wounded with four bullets.

While the Saints were in Missouri the Lord commanded that they should importune the officers of the law in the districts where the trouble occurred, and not being heeded, should appeal to the governor, thence to the president of the United States. All this was done, without avail. The president answered their appeal by saying, "Gentlemen, your cause is just, but I can do nothing for you." Governors of states were written to, to use their influence to avert the wrongs heaped upon the Saints, but from one or two only came a favorable response. On the failure of the states and nation to protect their own citizens against mob violence and plunder, the Lord promised to vex the nation with a sore vexation. This was done in the hundreds of thousands of lives and the millions in treasure lost in the Civil War. The outbreak of this war was revealed by the Lord to Joseph twenty-eight years before it came to pass, and published to the world as early as 1851.

The Church was not founded by men, nor did it depend upon any particular man or set of men for strength, growth or progress. God has rounded and protected and is perpetuating His Church on the earth, so that when the Prophet passed to the life beyond, the work continued and grew with great rapidity. It is said, and truly, that "the blood of the martyr is the seed of the Church."

President Brigham Young and his associates of the Twelve, according to the voice of the Spirit and the order of the Holy Priesthood, succeeded to the Presidency of the Church. The work of the Lord continued to prosper, contrary to the prediction of its enemies that when the Prophet Joseph was out of the way the work would come to naught. The foundation of a temple had been laid which was pushed to completion, dedicated to the Lord, and ordinances performed therein. Mobocratic hostilities were renewed, however, with determined vigor. Nauvoo was besieged. The temple was burned and Elder William Anderson and his son killed. The Saints were expelled at the point of the bayonet. They had a flourishing city in an incredibly short time. They were quiet, peaceable, law-abiding, industrious citizens. The killing of their leading men, the burning of their homes, the numerous indignities heaped upon them, were as dastardly and cold-blooded as any persecution chronicled in the annals of history, especially when we consider that it occurred in a free country, where liberty for every race and religion is the proud boast of its people. Many of the people left Nauvoo in the dead of winter, 1845-6, crossing the Mississippi river on the ice. The day after the general exodus, nine children were born in the camp of the exiled people. Under the leadership of President Young and his associates, the Saints moved westward across the state of Iowa and built up a settlement called Winter Quarters, where the people remained to recruit until 1847. While there the government called on the Saints for five hundred men to engage in the war with Mexico. These were promptly supplied, and the most able-bodied men were sent to defend their country.

In the spring of 1847, President Young and a small company numbering 143, including three women, started from the Missouri river to find beyond the Rocky Mountains a place of rest, where they might build and inhabit homes and worship God "free from the furious rage of mobs." After an interesting and trying journey of about three months this noble band of pioneers entered Salt Lake valley July 24th, 1847, over a thousand miles from the Mississippi river. As they emerged from the mouth of what was afterwards named Emigration Canyon, they stood upon a plateau facing westward. To the north and south a great valley extended, bordered on the west by mountains and a great inland sea of salt water, the Great Salt Lake. The islands in the lake are mountains almost destitute of timber, but supplied with grass suitable for the grazing of horses and cattle. The valley was poorly watered, and dry and sterile was the appearance of the country before them. But God was their leader. He had shown to President Young beforehand the Salt Lake Valley. When the pioneer band entered the valley the Prophet said, "This is the place. Here we will build a city." When they came upon the ground where the temple now stands, President Young, thrusting his cane into the ground, said in substance, "Here we will stay, and upon this ground we will build a temple."

All the events conducing to the growth and development of the valleys prove that President Brigham Young knew whereof he spoke, and God has confirmed his words by the many blessings of divine Providence showered upon the people in building up a commonwealth in what was in those days a great barren waste. The soil upon which the Saints then stood belonged to Mexico. Those pioneers were as truly exiles from their country as were the Puritans who sailed the trackless ocean and planted their feet upon Plymouth Rock. And yet the Latter-day Saints then had five hundred men in the American army, in the contest with Mexico. Upon a prominent mountain peak, called Ensign, the "Mormon" pioneers planted the Stars and Stripes, the flag of their country, and possessed the land as citizens of the United States. Upon the arrival of this first company the work of plowing and building immediately commenced. It would take volumes to tell the history of the growth and progress of the Saints from that time till now; but this wondrous recital is written upon the mountains and in the valleys, which are open to the inspection of all people.

In the fall of 1847 a large company of Saints crossed the plains, led by President John Taylor and other prominent men. The companies continued to pour into Salt Lake valley and spread into the valleys north and south each year from 1847 to 1900, coming as Latter-day Saints, under the regulations of the Church. The leading brethren had made covenant that they would not cease their energies until all the Saints who would remain faithful should be gathered to the place appointed.

Before the death of Prophet Joseph many had apostatized. The Saints were not so well established in doctrine as they are today, and some were led astray by the pretensions of prominent men who were disposed to leave the Church and follow their own course. The Twelve Apostles stood next in authority to the Presidency of the Church by the order pointed out in the revelations of God and at the time when Sidney Rigdon was asserting his claims to the guardianship of the Church, President Young stood up to address the Saints. A remarkable manifestation of God's power took place. President Young was transfigured before the people. He appeared to increase in height and in form of his face and body to the exact personal appearance of the Prophet Joseph Smith. When he spoke his voice was as that of the martyred Prophet. People who were present on that occasion say that if their eyes had been closed when he arose from his seat they would have believed the speaker to be none other than the Martyr. Truly the mantle of Joseph had fallen upon Brigham, and while Joseph had received all the keys of the priesthood, he had bestowed them upon the Twelve, also the revelations upon which to build the Church of Christ. President Young truly built upon these revelations during his entire administration. In 1849, at Winter Quarters, he was sustained as President of the Church by the unanimous voice of the priesthood, Heber C. Kimball and Willard Richards then being chosen Counselors and so endorsed by the voice of the Church thereafter at general conferences during the remainder of their lifetimes. President Young presided over the Church as the senior Apostle for thirty-three years, five years in connection with the Twelve and twenty-eight years in the Presidency.

Soon after the settlement of the Saints in Salt Lake valley, other valleys were explored north and south, and settlements established wherever water could be obtained, as rapidly as the strength and numbers of the Saints would justify. As early as 1860 settlements were rounded and the Saints organized in Wards and quorums of the priesthood, from Cache valley to St. George, a distance of over 400 miles from north to south. Wherever the Saints locate in settlements of a few families, or more, they are organized with a Bishop and counselors to preside over them, with Priests, Teachers and Deacons, as before explained, for a local ministry. As helps in government they had in those early days the Relief Society to relieve the poor and afflicted. The society is composed of women, and was first organized March 17, 1842, by the Prophet Joseph Smith, in Nauvoo. In 1849 the first Sunday school was established in the Church by Richard Ballantyne, in the Fourteenth Ward, Salt Lake City. Later, and during the administration of President Young, the Young Men and Young Ladies' Mutual Improvement Associations were inaugurated. Still later, by suggestion of Sister Aurelia Spencer Rogers, under the administration of President John Taylor, the Primary Associations, presided over and conducted by capable sisters, were established for the especial benefit of little children. All these are helpful regulations to meet the growing requirements of the Saints in matters of religious, moral and intellectual training and development. One of these organizations exists in every Bishop's Ward, unless the number of any class who properly belong to one of the associations named is too limited to make the organization profitable. In such cases those who would take part in such associations are not unprovided for because the Sunday school, more than any other association in the Church, takes in all ages of both sexes. Our Sunday schools now have a membership of nearly 125,000.