The Book of Mormon, Alma 12:16-18
16 And now behold, I say unto you then cometh a death, even a second death, which is a spiritual death; then is a time that whosoever dieth in his sins, as to a temporal death, shall also die a spiritual death; yea, he shall die as to things pertaining unto righteousness.
17 Then is the time when their torments shall be as a lake of fire and brimstone, whose flame ascendeth up forever and ever; and then is the time that they shall be chained down to an everlasting destruction, according to the power and captivity of Satan, he having subjected them according to his will.
18 Then, I say unto you, they shall be as though there had been no redemption made; for they cannot be redeemed according to God’s justice; and they cannot die, seeing there is no more corruption.
The Doctrine and Covenants, Section 29:26-30
26 But, behold, verily I say unto you, before the earth shall pass away, Michael, mine archangel, shall sound his trump, and then shall all the dead awake, for their graves shall be opened, and they shall come forth–yea, even all.
27 And the righteous shall be gathered on my right hand unto eternal life; and the wicked on my left hand will I be ashamed to own before the Father;
28 Wherefore I will say unto them–Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels.
29 And now, behold, I say unto you, never at any time have I declared from mine own mouth that they should return, for where I am they cannot come, for they have no power.
30 But remember that all my judgments are not given unto men; and as the words have gone forth out of my mouth even so shall they be fulfilled, that the first shall be last, and that the last shall be first in all things whatsoever I have created by the word of my power, which is the power of my Spirit.
The Doctrine and Covenants, Section 88:102
102 And another trump shall sound, which is the fourth trump, saying: There are found among those who are to remain until that great and last day, even the end, who shall remain filthy still.