In Article #4 of the Articles of Faith, we read,
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.
This statement is important enough for the Savior to declare it to be the "doctrine of Christ" (3 Nephi 11). Let's look at these one at a time first.
In the Lectures on Faith, we learn,
Faith, being the first principle in revealed religion, and the foundation of all righteousness, necessarily claims the first place in a course of lectures which are designed to unfold to the understanding the doctrine of Jesus Christ.
Here we find that faith is not only the first principle, but it is the foundation for all righteousness. We cannot be fully righteous without first having faith in Jesus Christ!
The Lectures on Faith teach that faith is the "moving cause" in all action both temporal and spiritual. Before a person goes to off to work, she has faith that her employer will pay her wages at the end of the week. We exercise faith in termporal things everyday we arise and do the things we do, because we believe our actions will provide a benefit. That faith is based upon experience, that which we have observed occur in others' lives, and that which happens in our own.
So it is in spiritual things. We follow Christ because our belief in him creates a moving power or action within us. It begins the process of the "doctrine of Christ" in our lives, and without faith, repentance, ordinances and the Spirit cannot work.
So powerful is faith that God used faith to frame the worlds and all his creations.
Had it not been for the principle of faith, the worlds would had never been framed, neither would man have been formed of the dust. It is the principle by which Jehovah works, and through which he exercises power over all temporal as well as eternal things. Take this principle or attribute - for it is an attribute - from the Deity, and he would cease to exist.
Faith being so important for the creation of the worlds, how important then is it for us to develop faith in regards to our own salvation?
Once we develop a faith in Christ, we will recognize our weaknesses and sins. We will want to follow him, as faith is a "moving cause."
Repentance is the actions needed to realign ourselves with Christ and his will. It requires humility and a willingness to change. Without repentance, we remain stagnant and unable to develop faith in Christ. The Lord warned us about the importance of repentance:
Therefore I command you to repent—repent, lest I smite you by the rod of my mouth, and by my wrath, and by my anger, and your sufferings be sore—how sore you know not, how exquisite you know not, yea, how hard to bear you know not.
For behold, I, God, have suffered these things for all, that they might not suffer if they would repent;
But if they would not repent they must suffer even as I;
Which suffering caused myself, even God, the greatest of all, to tremble because of pain, and to bleed at every pore, and to suffer both body and spirit—and would that I might not drink the bitter cup, and shrink—
Nevertheless, glory be to the Father, and I partook and finished my preparations unto the children of men.
Wherefore, I command you again to repent, lest I humble you with my almighty power; and that you confess your sins, lest you suffer these punishments of which I have spoken, of which in the smallest, yea, even in the least degree you have tasted at the time I withdrew my Spirit. (D&C 19:15-20)
We only suffer for the things we refuse to repent of. Yet, the suffering is so intense that we would suffer even as Christ did. For Alma the Younger, we learn that his suffering lasted 3 days, with a pain that was so "exquisite", he wished to stop existing entirely. Only when he exercised faith in Christ and repented, was he rescued from the intense and racking pain, and was filled with joy as exquisite as was his pain a moment before (Alma 36). Those who absolutely refuse to ever repent will be sons of Perdition. There is no salvation for them, because they would rather suffer the intense pains of hell than to beg forgiveness of the Lord.
The best time to repent is now. Still, even in the Spirit World, the Lord will open the door of salvation to any who believe and repent.
Baptism and other Ordinances
Many churches do not believe that baptism or other outward ordinances are necessary for salvation. They are right. A basic salvation in the Telestial Kingdom only requires faith and repentance, and it seems that repentance and redemption come at the last moment.
And again, we saw the glory of the telestial, which glory is that of the lesser, even as the glory of the stars differs from that of the glory of the moon in the firmament.
These are they who received not the gospel of Christ, neither the testimony of Jesus.
These are they who deny not the Holy Spirit.
These are they who are thrust down to hell (in Spirit Prison - until they repent and are redeemed at the last).
These are they who shall not be redeemed from the devil until the last resurrection, until the Lord, even Christ the Lamb, shall have finished his work....
And also the telestial receive it of the administering of angels who are appointed to minister for them, or who are appointed to be ministering spirits for them; for they shall be heirs of salvation. (D&C 76:81-88)
However, salvation in a Celestial Glory DOES require baptism. It is the gate that opens to God's full kingdom and glory. Baptism, the Sacrament (Holy Supper), and other ordinances of salvation are necessary for us, not only because of the covenants made, but also because of what the ordinances reveal to us.
And this greater priesthood administereth the gospel and holdeth the key of the mysteries of the kingdom, even the key of the knowledge of God.
Therefore, in the ordinances thereof, the power of godliness is manifest.
And without the ordinances thereof, and the authority of the priesthood, the power of godliness is not manifest unto men in the flesh;
For without this no man can see the face of God, even the Father, and live. (D&C 84:19-22)
The ordinances of baptism, the Sacrament, priesthood ordination, temple endowment and sealings, all reveal to us the "power of godliness." We receive the key to the knowledge of God as we receive ordinances and make the covenants eternally connected to those ordinances. In the instance of baptism, it opens the gate to heaven, so we can return back into God's presence and know him.
Gift of the Holy Ghost
While we receive this gift officially through an ordinance of laying on of hands by those in authority, it is significant to see how it works. No one lays his hands upon the person and says, "I bestow the gift of the Holy Ghost." Instead, the gift is received by commandment: "Receive the Holy Ghost!"
It is then our responsibility to actually receive the gift and accept it. The Holy Ghost can be a constant companion, but only when we are ready to have Him as a constant companion. Until then, he will come and go, as we are ready to receive him or not.
Note that after baptism, the Holy Ghost is received. He is a member of the Godhead. We now have communication with a member of the Godhead, as the mystery of godliness is revealed to us.
The Holy Ghost's main calling is twofold: to witness of the Father and Son, and to sanctify us (Mosiah 4:1-4).
A Pattern to Live By
It isn't that we gain faith once, or repent once, or receive an ordinance once, and then we are finished. Instead, we have been given a pattern by which we should live our lives. It becomes a process:
1. Gain faith in Christ to a certain level
2. Realize we have weaknesses to overcome and Repent
3. Receive the ordinances necessary to move forward at this level of faith
4. Have the Holy Ghost sanctify us to a new level of faith and righteousness
5. Rinse and repeat
This is a process or pattern established by Jesus.
And I, John (the Apostle), saw that he (Christ) received not of the fulness at the first, but received grace for grace;
And he received not of the fulness at first, but continued from grace to grace, until he received a fulness;
And thus he was called the Son of God, because he received not of the fulness at the first. (D&"C 93:12-14)
As with Jesus, we must proceed from grace to grace, receiving grace for grace. As we develop a level of faith and repentance, we then receive an ordinance/covenant to that level. Then, the Holy Ghost sanctifies us to that new level of grace. In this pattern, we can develop perfection over time through Christ, and receive a fulness, even as he did.
Lectures on Faith: http://archive.org/stream/compilationconta00lund#page/6/mode/2up