D&C 64:7; 76:31-37; Rev. 20:12-15; Hel. 14:15-18; 2 Ne. 9:15-16; Doctrines of Salvation, Smith, 2:224-225
“Thus, eventually, all are redeemed from spiritual death except those who have ‘sinned unto death’ (D&C 64:7), that is, those who are destined to be sons of perdition.” (Bruce R. McConkie, Mormon Doctrine, p.758)
“Where is the spirit world? It is right here… . Can you see it with your natural eyes? No. Can you see spirits in this room? No. Suppose the Lord should touch your eyes that you might see, could you then see the spirits? Yes, as plainly as you now see bodies… .” (Discourses of Brigham Young, pp. 376-377)
[Following death] “The spirits of the just are … blessed in their departure to the world of spirits… . They are not far from us, and know and understand our thoughts, feelings, and motions, and are often pained therewith… .” (Teachings of the Prophet Joseph Smith, p. 326)
“Many spirits of the departed, who are unhappy, linger in lonely wretchedness about the earth, and in the air, and especially about their ancient homesteads, and the places rendered dear to them by the memory of the former scenes.” (Parley P. Pratt, Key to the Science of Theology, p. 117)
“We have more friends behind the veil than on this side, and they will hail us more joyfully than you were ever welcomed by your parents and friends in this world; and you will rejoice more when you meet them than you ever rejoiced to see a friend in this life; and then we shall go on from step to step, from rejoicing to rejoicing, and from one intelligence and power to another, our happiness becomes more and more exquisite and sensible as we proceed… .” (Discourses of Brigham Young, pp. 379-380)
“Brother Joseph Smith gave an explanation of [evil influences]. There are places in the Mississippi Valley where the influence or the presence of invisible spirits are very perceptibly felt. He said that numbers had been slain there in war and that there were evil influences or spirits which affect the spirits of those who have tabernacles on the earth. I myself have felt those influences in other places besides the continent of America; I have felt them on the old battle grounds on the Sandwich Islands. I have come to the conclusion that if our eyes were open to see the spirit world around us, we should feel differently on this subject than we do; we would not be so unguarded and careless and so indifferent whether we had the spirit and power of God with us or not; but we would be continually watchful and prayerful to our Heavenly Father for His Holy Spirit and His holy angels to be around about us to strengthen us to overcome every evil influence.” (George Q. Cannon, Gospel Truths, 1:82)
“I know it is a startling idea to say that the Prophet and the persecutor of the Prophet, all go to prison together. What is the condition of the righteous? They are in possession of the spirit of Jesus—the power of God… . Jesus will administer to them; angels will administer to them; and they have a privilege of seeing and understanding more than you or I have, in the flesh; but they have not got their bodies yet, consequently they are in prison… . What is the condition of the wicked? They are in prison. Are they happy? No… .” (Brigham Young, Journal of Discourses 3:95)
“When our spirits leave these bodies, will they be happy? Not perfectly so. Why? Because the spirit is absent from the body; it cannot be perfectly happy while a part of the man is lying in the earth.” (Orson Pratt, Journal of Discourses 1:289-290)
“Every man that has been baptized and belongs to the kingdom has a right to be baptized for those who have gone before; and as soon as the law of the Gospel is obeyed here by their friends who act as proxy for them, the Lord has administrators there to set them free.” (Teachings of the Prophet Joseph Smith, p. 367)
“… many other great truths not known before, have been declared to the people, and one of the greatest is that to hell there is an exit as well as an entrance. Hell is no place to which a vindictive judge sends prisoners to suffer and to be punished principally for his glory; But it is a place prepared for the teaching, the disciplining of those who failed to learn here upon the earth what they should have learned… . No man will be kept in hell longer than is necessary to bring him to a fitness for something better. When he reaches that stage the prison doors will open and there will be rejoicing among the hosts who welcome him into a better state.” (James E. Talmage, Conference Report, Apr. 1930, p. 97)
“The work of the righteous is to preach the gospel to as many as will receive it, so that whosoever receives it unto repentance may leave the spirit prison and enter into paradise when the ordinances have been done vicariously for them on earth. Through the institution of baptism for the dead, the Church is able to open the gate of baptism, which allows the repentant spirits to exit the spirit prison of hell, the state of the wicked in the spirit world.” (Richard O. Cowan, Alma, The Testimony of the Word, ed. by Nyman and Tate, p. 184)