Alma 42:16 - 42:20
Alma 42: 16 Now, repentance could not come unto men except there were a punishment, which also was eternal as the life of the soul should be, affixed opposite to the plan of happiness, which was as eternal also as the life of the soul.
The reason there is punishment is that men would not repent unless it hanging over one’s head. Punishment for infractions is just as eternal as one’s own spirit. And it is opposite to the plan of happiness which is just as eternal.
Alma 42: 17 Now, how could a man repent except he should sin? How could he sin if there was no law? How could there be a law save there was a punishment?
Now a man cannot sin if there is no law. But there are laws. However, they would be ignored if there was not punishments affixed to the laws when they are violated.
Alma 42: 18 Now, there was a punishment affixed, and a just law given, which brought remorse of conscience unto man.
But as we all know, there are punishments attached to laws. You violate a law you stand in violation of them and are subject to whatever punishments are attached to them. Knowing that there are punishments to laws caused men to think twice about violating them.
Now whether, it brothers some folks who do violate laws and really don’t care is another matter. They might fear the punishments but they may not really care if they violate them; they only fear being caught not the law itself. They just may not care if it hurtful to others because they hate others and are only concerned about themselves.
Alma 42: 19 Now, if there was no law given—if a man murdered he should die—would he be afraid he would die if he should murder?
Having punishments make people afraid of being caught and punished. So if there was no law against murder, who would be afraid of killing?
Alma 42: 20 And also, if there was no law given against sin men would not be afraid to sin.
The same applies to any sin. Who would be afraid to sin if there was no punishment against it?
Again, this bring up the idea, would you not sin because you are afraid of consequences or are you afraid to sin because it would be hurtful against others and because you love people you do not want to cause any problems for them? I think those who are afraid to sin because of punishments are not the kind of people who will be in heaven. It will be those who do not want to sins because of the effects of sins on others and themselves.