Before I went east on the 4th of April  last, we were in council with Brother Joseph almost every day for weeks; said Brother Joseph in one of those councils, “There is something going to happen; I don’t know what it is, but the Lord bids me to hasten and give you your endowment before the Temple is finished.” He conducted us through every ordinance of the holy priesthood, and when he had gone through with all the ordinance he rejoiced very much, and said, “Now if they kill me, you have got all the keys, and all the ordinances, and you can confer them upon others, and the hosts of Satan will not be able to tear down the kingdom as fast as you will be able to build it up”; and now, said he, “On your shoulders will the responsibility of leading this people rest.”1
Heber C. Kimball also recorded,
During this time many great and marvelous visions were seen, one of which I will mention which Joseph the Prophet had concerning the Twelve. His anxiety was and had been very great for their welfare, when the following vision was manifested to him, as near as I can recollect:
He saw the Twelve going forth, and they appeared to be in a far distant land. After some time they unexpectedly met together, apparently in great tribulation, their clothes all ragged, and their knees and feet sore. They formed into a circle, and all stood with their eyes fixed upon the ground. The Savior appeared and stood in their midst ad wept over them, and wanted to show Himself to them, but they did not discover Him. He (Joseph) saw until they had accomplished their work, and arrived at the gate of the celestial city; there Father Adam stood and opened the gate to them, and as they entered he embraced them one by one and kissed them. He then led them to the throne of God, and then the Savior embraced each one of them in the presence of God. He saw that they all had beautiful heads of hair and all looked alike. The impression this vision left on Brother Joseph’s mind was of so acute a nature, that he never could refrain from weeping while rehearsing it.2
It was during this time that the Nauvoo Council of Fifty convinced Joseph to run for President of the United States, the purpose of which was two fold; first to preach the gospel and second to lay the sufferings of the Saints out to the Nation. The Apostles then spread out across the country. Only John Taylor, who was in charge of Church publication, and Willard Richards, who was in charge of keeping the Historical Record, remained in Nauvoo and stayed with the Prophet in Carthage Jail.
On June 27, at about a quarter past five in the evening, varying emotions came across the Quorum in whatever place they were laboring.
Orson Hyde stated, “he felt very heavy and sorrowful in spirit, and knew not the cause, and walked the floor; tears ran down his face. He never felt so before, and knew no reason why he should feel so then.”3
George A. Smith was traveling through Michigan, felt unusually cast down and depressed in spirits. About five o’clock he repaired to an oak grove, and called upon the Lord, endeavoring to break the spell of horror which had dominion over his mind. He remained there a long time without finding any relief . . . “4
Parley P. Pratt remembered,
A day or two previous to this circumstance I had been constrained by the Spirit to start prematurely for home, without knowing why nor wherefore; and on the same afternoon I was passing on a canal boat near Utica, New York, on my way to Nauvoo. My brother, William Pratt, being then on a mission in the same state (New York) happened, providentially, to take passage on the same boat. As we conversed together on the deck, a strange and solemn awe came over me, as if the powers of hell were let loose. I was so overwhelmed with sorrow I could hardly speak; and after pacing the deck for some time in silence, I turned to my brother, William, and exclaimed, ‘Brother William, this is a dark hour; the powers of darkness seem to triumph, and the spirit of murder is abroad in the land; and it controls the hearts of the American people, and a vast majority of them sanction the killing of the innocent. My brother, let us keep silence and not open our mouths. If you have any pamphlets or books on the fulness of the gospel lock them up; show them not, neither open your mouth to the people; let us observe an entire and solemn silence, for this is a dark day, and the hour of triumph for the powers of darkness.5
With the apostasy of Thomas B. Marsh, and the martyrdom of David W. Patten several years earlier in Far West, Brigham stood as President of the Quorum of the Twelve. Wilford Woodruff recalled,
The day of the martyrdom, Brigham Young and myself were seated in the railroad station at the time Joseph and Hyrum were assassinated. This was June the 27th, at quarter past five in the evening, at Carthage, Illinois. It was half-past sixin Boston. As we sat in the station, Brigham was very sorrowful and depressed in spirit, not knowing the cause.6
A couple of days later they received a telegram bringing the news. Brigham recorded,
The first thing which I thought of was, whether Joseph had taken the keys of the kingdom with him from the earth; Brother Orson Pratt sat on my left; we were both leaning back on our chairs. Bringing my hand down on my knee, I said the keys of the kingdom are right here with the Church.7
As the Apostles finally arrived back in Nauvoo, they found several brethren claiming the right to be the new President of the Church. sidney rigdon, who had left the Church and took a handful of Saints with him to New York, claimed that he should be appointed “guardian” over the Church and that there could be only one President / Prophet – Joseph Smith. A meeting was called, and Rigdon spoke for an hour and a half. Brigham Young then spoke for less than ten minutes saying that he didn’t care who led the Church, but wanted to know what God wanted. He also pointed out that if the Saints were to call a guardian, only the Twelve had the authority to ordain someone to such a calling and that he didn’t think that was going to happen any time soon. There are over fifty recorded accounts of the mantle of Joseph Smith falling upon Brigham Young, that he looked like and even sounded like Joseph Smith. A sustaining vote was called in the affirmative of the Twelve. Sidney Rigdon went back to New York and died many years later alone and still very bitter.
It wasn’t until after Brigham Young had reached the Salt Lake Valley that he felt impressed to reorganize the First Presidency. The Twelve then turned back to Winter Quarters, Iowa where the majority of the Saints were preparing themselves to continue west. Orson Hyde spoke of what happened next.
In the month of February, 1848, the Twelve Apostles met at Hyde Park, Pottawattamie County, Iowa, where a small Branch of the Church was established. . . . We were in prayer and council, communing together; and what took place on that occasion? The voice of God came from on high, and spake to the Council. Every heart melted. What did it say unto us? “Let my servant Brigham step forth and receive the full power of the presiding Priesthood in my Church and kingdom.” … I am one that was present, and there are others here that were also present on that occasion, and did hear and feel the voice from heaven, and we were filled with the power of God. This is my testimony; these are my declarations unto the Saints—unto the members of the kingdom of God in the last days, and to all people.
. . . Men, women, and children came running together where we were, and asked us what was the matter. They said that their houses shook, and the ground trembled, and they did not know but that there was an earthquake. We told them that there was nothing the matter—not to be alarmed; the Lord was only whispering to us a little, and that he was probably not very far off. We felt no shaking of the earth or of the house, but were filled with the exceeding power and goodness of God. We knew and realized that we had the testimony of God within us. ….then, held in the Log Tabernacle at Kanesville, the propriety of choosing a man to preside over the Church was investigated. In a very few minutes it was agreed to, and Brigham Young was chosen to fill that place without a dissenting voice, the people not knowing that there had been any revelation touching the matter. They seconded the voice of the Lord from on high in his appointment. Yes, the voice of God was the voice of the people. Brigham went right ahead, silently, to do the work of the Lord, and to feed his sheep, and take care of them like a faithful shepherd.8
1 – Jedediah M. Grant, Collection of Facts Relative to Sidney Rigdon, P. 24-25
2 – Orson F. Whitney. Life of Heber C. Kimball, P. 93-94
3 – Myrle Stevens Hyde, Orson Hyde: The Olive Branch of Israel, P. 175
4 – History of the Church, Vol. 7, P. 133
5 – Autobiography of Parley P. Pratt, P. 292
6 – Matthias F. Cowley, Wilford Woodruff: His Life and Labors, P. 206
7 – Manuscript History of Brigham Young, P. 170-71
8 – Orson Hyde, Journal of Discourses, October 1860, Vol 8, P. 233-34