Faith is the First Principle - 3 Nephi 27:19-20

And no unclean thing can enter into his kingdom; therefore nothing entereth into his rest save it be those who have washed their garments in my blood, because of their faith, and the repentance of all their sins, and their faithfulness unto the end. Now this is the commandment: Repent, all ye ends of the earth, and come unto me and be baptized in my name, that ye may be sanctified by the reception of the Holy Ghost, that ye may stand spotless before me at the last day.

 In this scripture we have all of the first principles and ordinances of the gospel:

We believe that the first principles and ordinances of the Gospel are: first, Faith in the Lord Jesus Christ; second, Repentance; third, Baptism by immersion for the remission of sins; fourth, Laying on of hands for the gift of the Holy Ghost. (4th article of faith)

Faith is the first principle, and is the thing that propels us forward. Remember that faith and belief, though related, are not the same. While belief is a function of the head, faith is a function of the heart. In other words, although I may be convinced of some principle, I may not live according to it. On the other hand, one must have belief before faith, and live the principle. A man may believe that God has the ability to help him, but may out of fear of the world, choose actions contrary to that belief. Belief knows that God can save him from the fiery furnace, faith steps inside.

But why the emphasis on faith? Why is it the first principle? This scripture and others make it very clear: no unclean thing can enter into His kingdom.

... for the day should come that they must be judged of their works, yea, even the works which were done by the temporal body in their days of probation. ... and if their works have been filthiness they must needs be filthy; and if they be filthy it must needs be that they cannot dwell in the kingdom of God; if so, the kingdom of God must be filthy also. But behold, I say unto you, the kingdom of God is not filthy, and there cannot any unclean thing enter into the kingdom of God; wherefore there must needs be a place of filthiness prepared for that which is filthy. (1 Nephi 15:32-34)

If any unclean person (or thing) were allowed to come into the Kingdom of Heaven, it would cease to be Heaven. Simple as that. But that puts us in a predicament because none of us are clean:

For all have sinned, and come short of the glory of God; (Romans 3:23)

Furthermore, our cause is really hopeless if we if we think we can work our way to heaven or rely on our own merits:

And now, in the first place, he hath created you, and granted unto you your lives, for which ye are indebted unto him. And secondly, he doth require that ye should do as he hath commanded you; for which if ye do, he doth immediately bless you; and therefore he hath paid you. And ye are still indebted unto him, and are, and will be, forever and ever; therefore, of what have ye to boast? And now I ask, can ye say aught of yourselves? I answer you, Nay. Ye cannot say that ye are even as much as the dust of the earth; yet ye were created of the dust of the earth; but behold, it belongeth to him who created you.(Mosiah 2:23-25)

Quite frankly, we're all going to hell. But doesn't God love us? Doesn't he want to save everybody? Why these harsh constraints about being perfectly clean? He knows we aren't capable of such a level of perfection right?

Enter Jesus Christ.

God loves us so much, that he provided a way for us to be clean. But it would require the permission of utter ruthlessness and violence to be perpetrated on an innocent victim. Who would volunteer for such an assignment? The only one strong enough and manly enough to cope with all hell, torture, violence, depravity and injustice. One stronger than all, and yet meek enough to volunteer for such a job.

Accepting Jesus Christ as your Savior is an admission that you need help. It is a declaration of spiritual bankruptcy. Such a declaration requires a meek and repentant heart. It is acknowledging that you've committed grave injustices in your life, and that you have no power to set things right. While this is a very sobering admission, it is a liberating one. It is to look at our state as it really is: worthless and fallen. It is the first step to repentance and true joy.

... even so I would that ye should remember, and always retain in remembrance, the greatness of God, and your own nothingness, and his goodness and long-suffering towards you, unworthy creatures, and humble yourselves even in the depths of humility, calling on the name of the Lord daily, and standing steadfastly in the faith ... (Mosiah 4:11)

... as I was thus racked with torment, while I was harrowed up by the memory of my many sins, behold, I remembered also to have heard my father prophesy unto the people concerning the coming of one Jesus Christ, a Son of God, to atone for the sins of the world. Now, as my mind caught hold upon this thought, I cried within my heart: O Jesus, thou Son of God, have mercy on me, who am in the gall of bitterness, and am encircled about by the everlasting chains of death. And now, behold, when I thought this, I could remember my pains no more; yea, I was harrowed up by the memory of my sins no more. And oh, what joy, and what marvelous light I did behold; yea, my soul was filled with joy as exceeding as was my pain! (Alma 36:17-20)

The admonition is simple: declare bankruptcy. Shout it from the rooftops! And enter in at the straight and narrow gate, stripped of pride, gain-seeking and all other diversions. Remember that the last shall be first, and the first shall be last and deny yourself of all ungodliness:

Yea, come unto Christ, and be perfected in him, and deny yourselves of all ungodliness; and if ye shall deny yourselves of all ungodliness, and love God with all your might, mind and strength, then is his grace sufficient for you, that by his grace ye may be perfect in Christ; and if by the grace of God ye are perfect in Christ, ye can in nowise deny the power of God. And again, if ye by the grace of God are perfect in Christ, and deny not his power, then are ye sanctified in Christ by the grace of God, through the shedding of the blood of Christ, which is in the covenant of the Father unto the remission of your sins, that ye become holy, without spot. (Moroni 10:32-33)

It turns out that the low road of discipleship, if taken seriously is not burdensome, but joyous, not because it isn't a difficult road, but because we do not travel alone:

Come unto me, all ye that labour and are heavy laden, and I will give you rest. Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. For my yoke is easy, and my burden is light. (Matt 11:28-30)