Why should we keep Lower Law?

When Moses came down from Mount Sinai and saw his people worshiping a golden calf, he threw down the tablets with the law God had written with his finger. He went back and came again with the Ten Commandments, which were according as, but different than the first set. In the LDS Church we frequently call this the lower law. We know that the Law of Moses still contained the gospel of faith, repentance and baptism, but it also had carnal commandments adapted for the Israelites and their struggle to keep God's commandments.



Lower laws are just as important to keep as higher laws.
This might not be intuitive from the typical teenage experience. When a parent sets a curfew, they might set it a few minutes early in case the kid is late. When designing a car or mechanical system, the engineer calculates the threshold of performance and gives additional leniency for errors in manufacturing, materials, and wear. However, God doesn't give commandments intending them to be broken. (See number 3 below about the Nephites)

Here are a few things we can learn from this "Lower Law" about obedience in our lives today.

We grow from grace to grace; we learn line upon line.
       Part of being human is having and overcoming failings, ignorance, and mistakes. Through John the Beloved, we know that even Jesus grew from grace to grace. This is a true principle for each of us as we repent and try doing our best. When we can keep the commandments we have been given, God allows us to repent by increasing our goals. His ultimate commandment is "Be ye therefore perfect" which shows us that he truly wants us to come to his level eventually.

We are accountable according to our knowledge.
       I believe knowledge and commandments are two major factors in determining our accountability. A third important factor is intent, a topic for another time. God has told us that he who sins against the greater light shall receive the greater condemnation. This is a very merciful principle because the Lord doesn't give us all knowledge at once. If the Lord were to reveal all truth to us at once, we would immediately be accountable to be perfect as He is. Instead, he allows us to grow and learn from our mistakes. Being the Perfect Judge, he knows when we fail because of true ignorance and is merciful.

We are accountable according to the commandments.
     We are also accountable according to the commandments. The Nephites, for example, knew that the Law of Moses was given for wickedness and that there was no salvation only through the law of Moses. For more on this topic, see Abinadi's teaching here. Nephi writes:

 24 And, notwithstanding we believe in Christ, we keep the law of Moses, and look forward with steadfastness unto Christ, until the law shall be fulfilled.

 25 For, for this end was the law given; wherefore the law hath become dead unto us, and we are made alive in Christ because of our faith; yet we keep the law because of the commandments.

(2 Ne 25:24-25 emphasis added)

      The Nephites in the Americas kept the Law of Moses until it was fulfilled even though they knew it wasn't a perfect law. None of them was even alive when the Israelite wickedness brought these laws about, nor were they even in the same continent - yet they kept the law!
      Consider how Christ clearly demonstrated accountability to the law. He kept the Law of Moses every whit even as he fulfilled it (see here and here). Christ was the Giver of the Law, and he knew better than anyone its weakness - yet he kept the law. Wasn't he exempt because he knew that was a lower law? No, even Jesus was accountable for the commandment regardless of what he knew or intended. His agony in Gethsemane and crucifixion on Calvary are the ultimate example of how real the law of justice is and how necessary it is to keep and fulfill the law. Knowledge and good intentions cannot justify breaking any law, even a lower law.

We are accountable to others' knowledge
      The Jews had a tradition refusing the meat sacrificed to idols in an effort to have nothing to do with idols and idol worship. Christ rejected many unnecessary traditions of the Jews, and the question about eating the meat sacrificed to idols came up among the Corinthians. Paul's response illustrates the group nature of the gospel, and how living the gospel is intended for everyone. Paul says that in reality, idols are not deities or powers and therefore the meat is not cursed or blessed by them. We are at liberty to eat or refuse the meat, but...

  9 But take heed lest by any means this liberty of yours become a stumbling block to them that are weak.
 10 For if any man see thee which hast knowledge sit at meat in the idol’s temple, shall not the conscience of him which is weak be emboldened to eat those things which are offered to idols;
 11 And through thy knowledge shall the weak brother perish, for whom Christ died?
 12 But when ye sin so against the brethren, and wound their weak conscience, ye sin against Christ.

According to Paul, other people's knowledge or lack of knowledge is a determinant of what constitutes sin. As an older sibling, this makes a lot of sense. I wasn't supposed to cross the street without my parents when I was younger. Even though I was old enough to cross the street safely, my siblings might have made bad decisions if they saw me crossing the road alone.
       
Conclusion
The idea of a law being lower or higher doesn't refer to the importance of obeying it. A law is lower when it is not true during all dispensations or if it will be fulfilled. I hope that you can recognize the importance of a lower law and how it is important to keep it. Lower laws in the church today might include the three hour church block and the Word of Wisdom (specifically tailored to the weakest of Saints!), and the missionary handbook while on a mission.  God gives us step-wise commandments to help us grow, to allow us to learn from smaller mistakes, to test our faith, and to test our self-control for the benefit of others.