D&C 19

Contrary to what some Christians believe, the Lord has declared that He will judge -

"...every man according to his works and the deeds which he hath done.
4 And surely every man must repent or suffer..." (Doctrine and Covenants Section 19:3 - 4)

Lehi taught that -

"...there is a law given, and a punishment affixed, and a repentance granted..." (Book of Mormon Alma 42:22)

The Lord has made it clear that though He is a loving and merciful God, He is also just saying -

"...I revoke not the judgments which I shall pass, but woes shall go forth, weeping, wailing and gnashing of teeth, yea, to those who are found on my left hand." (Doctrine and Covenants Section 19:5)

This doesn't mean that God's children will suffer "affixed" punishment for He explains -

"...it is not written that there shall be no end to this torment, but it is written endless torment." (Doctrine and Covenants Section 19:6)

Wherefore, I will explain unto you this mystery...For, behold, the mystery of godliness, how great is it! For, behold, I am endless, and the punishment which is given from my hand is endless punishment, for Endless is my name. Wherefore—
11 Eternal punishment is God's punishment.
12 Endless punishment is God's punishment." (Doctrine and Covenants Section 19:8 - 12)

There is a difference though between Endless punishment and Endless damnation. Elder Bruce R. McConkie explained -

“Eternal damnation is the opposite of eternal life, and all those who do not gain eternal life, or exaltation in the highest heaven within the celestial kingdom, are partakers of eternal damnation. Their eternal condemnation is to have limitations imposed upon them so that they cannot progress to the state of godhood and gain a fulness of all things.

They ‘remain separately and singly, without exaltation, . . . to all eternity; and from henceforth are not gods, but are angels of God forever and ever.’ (D. & C. 132:17.) Their kingdom or progress has an ‘end,’ and they ‘cannot have an increase.’ (D. & C. 131:4.) Spirit children are denied to them to all eternity, and they inherit ‘the deaths,’ meaning an absence of posterity in the resurrection. (D. & C. 132:16–25.)

They are never redeemed from their spiritual fall and taken back into the full presence and glory of God. Only the obedient are ‘raised in immortality unto eternal life.’ The disobedient, ‘they that believe not,’ are raised in immortality ‘unto eternal damnation; for they cannot be redeemed from their spiritual fall, because they repent not.’ (D. & C. 29:42–44.)” (Mormon Doctrine, p. 234.)

With all the love the Savior could express He explained -

"...I, God, have suffered these things for all, that they might not suffer if they would repent;
17 But if they would not repent they must suffer even as I;
18 Which suffering caused myself, even God, the greatest of all, to tremble because of pain, and to bleed at every pore, and to suffer both body and spirit..." (Doctrine and Covenants Section 19:16 - 18)

Is it any wonder, the Lord pleads over and over -

"I command you to repent—repent, lest I smite you by the rod of my mouth, and by my wrath, and by my anger, and your sufferings be sore—how sore you know not, how exquisite you know not, yea, how hard to bear you know not." (Doctrine and Covenants Section 19:15)

And -

"...I command you again to repent, lest I humble you with my almighty power; and that you confess your sins, lest you suffer these punishments of which I have spoken..." (Doctrine and Covenants Section 19:20)

And again -

"Wherefore, I command you to repent, and keep the commandments..." (Doctrine and Covenants Section 19:13)