The LAW

Section 42 of the Doctrine and Covenants is important because it is considered "the law."
This law is very similar to the one given to Moses which further supports the parallelism with the modern exodus of Brigham and the saints. I really like the laws because they emphasize the behavior of people in what is right in the sight of god, opposed to what might be legal.
Nowadays, we still live by the principles of these laws, but we are not commanded to take on a journey to a holier place--more like a holier state. We are called to physically "bloom where we are planted" but spiritually we are to embark on an eternal journey of progression, until we hit perfection. This perfection to me, doesn't mean not sinning; it means striving to be whole. When Jesus cured people he declared their sins forgiven them, and made them whole. Since I have to call upon God to be forgiven, all I can do is repent and try to be made whole. This completeness only comes with constant efforts guided by the Spirit. This Spirit is like our compass in our exodus back to salvation.
Another interesting point to the importance of this section is how they received the information: questions. To relate this to Pres. Uchtdorf's recent fireside, We were told that it isn't wrong to be curious as long as we do not doubt. We should ask questions to receive revelations. This is the how Joseph Smith was able to receive instructions on restoring the gospel and its proper order. If we want to receive specific instruction or laws, we must inquire of the Lord. It is such as simple endeavor, but so is the kingdom of God. It is as simple as a child asking something of a parent. We can make valuable decisions and preparations when we ask and follow the promptings of the Law given to us by the scriptures and personal revelation in response to the council in the inspired text.