Who are the only ones who will not be redeemed?
The sons of perdition
They are they who are the sons of perdition, of whom I say that it had been better for
them never to have been born;
For they are vessels of wrath, doomed to suffer the wrath of God, with the devil and his angels in eternity;
Concerning whom I have said there is no forgiveness in this world nor in the world to come -
Having denied the Holy Spirit after having received it ...
These are they who shall go away into the lake of fire and brimstone, with the devil and his angels -
And ... the only ones who shall not be redeemed.
Doctrine & Covenants 76:32