3 Nephi 11:37-41

37 And again I say unto you, ye must repent, and become as a little child, and be baptized in my name, or ye can in nowise receive these things.
38 And again I say unto you, ye must repent, and be baptized in my name, and become as a little child, or ye can in nowise inherit the kingdom of God.
39 Verily, verily, I say unto you, that this is my doctrine, and whoso buildeth upon this buildeth upon my rock, and the gates of hell shall not prevail against them.
40 And whoso shall declare more or less than this, and establish it for my doctrine, the same cometh of evil, and is not built upon my rock; but he buildeth upon a sandy foundation, and the gates of hell stand open to receive such when the floods come and the winds beat upon them.
41 Therefore, go forth unto this people, and declare the words which I have spoken, unto the ends of the earth.

(Book of Mormon | 3 Nephi 11:37 - 41)

We must repent of our sins and become as a little child before Christ. Little children are honest, and full of trust and faith. They are innocent, and typically born with the desire to do good. As we grow older we tend to become3 more cynical, selfish, less trusting of others.
The doctrine of Christ is simple, repent and be baptized. Christ is the rock of my salvation, the sure foundation. If I build on Him, I will be able to withstand the tides of temptation that sweep over the earth.