Your original quote was from the Book of Mormon. Can you provide evidence as to which law Mormon was referring to in his epistle?

"For behold that all little children are alive in Christ, and also all they that are without the law. For the power of redemption cometh on all them that have no law; wherefore, he that is not condemned, or he that is under no condemnation, cannot repent; and unto such baptism availeth nothing--" - Moroni 8:22

Now we know that the Law of Moses was fulfilled by Christ, as He was the one who gave the law to begin with. Why did He give it?

Now this Moses plainly taught to the children of Israel in the wilderness, and sought diligently to sanctify his people that they might behold the face of God;

But they hardened their hearts and could not endure his presence; therefore, the Lord in his wrath, for his anger was kindled against them, swore that they should not enter into his rest while in the wilderness, which rest is the fulness of his glory.

Therefore, he took Moses out of their midst, and the Holy Priesthood also;

And the lesser priesthood continued, which priesthood holdeth the key of the ministering of angels and the preparatory gospel;

Which gospel is the gospel of repentance and of baptism, and the remission of sins, and the law of carnal commandments, which the Lord in his wrath caused to continue with the house of Aaron among the children of Israel until John, whom God raised up, being filled with the Holy Ghost from his mother's womb.

• The reason for giving the Law of Moses was, as you said, because the people would not enter into the presence of God.
  
• The church members today have, for the most part, still not entered into God's presence.
  
• We live the same law discribed in D&C 84 that was attributed to those who are cursed for not entering into God's presence.
  
• This is a PREPARATORY law (& Gospel) given to prepare people to enter into God's presence.
  
• This preparatory law and gospel includes faith, repentance, baptism, and the law of Carnal commandments.
  
• The system is easy, break the carnal commandments and you need to repent. Breaking these commandments is a sin.
  
• The surprising conclusion is, No Lower/preparatory law = No Law of Carnal Commandments to break = no sin to repent from, no need to be saved from the punishment of a broken law.
  

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? - Alma 42:17

Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God,

Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment.

And this will we do, if God permit.

For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,

And have tasted the good word of God, and the powers of the world to come,

If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God fresh, and put him to an open shame. - Heb. 6:1-6

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?

And also, if there was no law given against sin men would not be afraid to sin. - Alma 42:19-20