This is a continuation of the warning. Nephi wants us to take quite seriously his warnings.
When you read words like these it becomes apparent the only safe way to measure his warning is to apply it directly and personally to ourselves. To think this was meant only for "others" is too complacent.
When the truth has made you angry, and you have forfeited the option of repentance extended to you, the "grasp of death" is upon you. You will remain subject to "death and hell." Being "seized" by these two things, as you stand before the "throne of God" you will be certain that there will be, for you, a continuation of "the deaths." (D&C 132: 25.)
Judgment is based "according to their works." (See also Rev. 20: 12-13; explained further in D&C 128: 6-8.) Joseph ties sealing power to these "works" which must be done under this authority and then recorded to become binding. This is the practice of the church. It is and has always been the practice of those having such authority. They not only perform the work, but upon having done so they create a record of having done so.
Upon being judged, they go "into the place prepared for them." This place is, for those who are grasped with "death and hell" called "a lake of fire and brimstone." A lake because it engulfs them so tightly they are flooded with the guilt. Fire because it is designed to purge and refine. Brimstone because of the bitterness of the experience. The torment there is "endless" meaning from God. (D&C 19: 4-12.)
This purging does not confer blessings, but merely balances out the claims of justice for those who would not accept mercy. (D&C 19: 15-19.)
Crying repentance is to warn, so the claims of justice may be avoided by obtaining mercy through Christ. Christ's mercy is offered to all, but will only be received in full by few. All will be resurrected because of His sacrifice (1 Cor. 15: 22), and those who died without law will not be punished for their ignorance (D&C 76: 71-72; D&C 45, 54), but to receive the full benefit of His atonement must do as He commands (D&C 132: 22-23).
Those who love others and want their eternal welfare will invite everyone to repent and come to Christ. The prospect of others suffering needlessly because they would not repent is a great horror to them. This is why Nephi's words are at times so blunt. This is why he wants to stir us all up to our terrible situation. It is merciful to speak to us in these frank terms.
I know some who have read these words of counsel from Nephi and find them objectionable. However, Isaiah spoke against those whose words were "smooth" but filled with deceit. (Isa. 30: 10.) To people who are content and filled with pride, it takes a great deal of candor to bring them to their senses. (Enos 1: 23.) Nephi's warnings are intended to save as many of the gentiles who read his record from self-destruction as he can bring to repentance. It is better for us to take counsel from his hand than to dismiss his teachings. He can only warn his readers. Since we are his readers, he must be speaking to us.