There are two paths that can be walked in this life:
13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it. (Matthew 7)
The wide path is found after the wide gate. This is by far the more popular choice: “many be called, but few chosen.” (Matthew 20:16) This is the default choice. It leads to “destruction.”
This path actually doesn’t go anywhere. It may keep us busy and give us the illusion of stable comfort, but because it is devoid of real growth, it can’t improve us. This path is insufficient here and hereafter.
The wide gate and wide path are inclusive. They are filled with people milling about, convinced that activity is the same as progress. This is where you end up by default. These people are a herd with a herd mentality. They do not question. They do not think. They do not search. They assume that whatever they think is right, and that what they know is all there is to know. This is not the way of truth.
The narrow path comes after the narrow gate. You can’t get on that path without going through the gate. Choosing the narrow gate requires you to seek for truth beyond what is believed by the majority of people. You have to question. You have to think. You have to assume that whatever you think is incorrect or incomplete. This is the way of truth.
An attempt has been made at least once in scripture to describe how one enters into the gate:
...do the things which I have told you I have seen that your Lord and your Redeemer should do; for, for this cause have they been shown unto me, that ye might know the gate by which ye should enter. For the gate by which ye should enter is repentance and baptism by water; and then cometh a remission of your sins by fire and by the Holy Ghost. (2 Nephi 31:17)
It is easy to get bogged down in parsing the details of this description. What is repentance? What is the significance of baptism by water? What is remission of your sins? What does it mean to have it “by fire and by the Holy Ghost”?
Here is a more specific description untied from deeper concepts: You enter the gate by dedicating yourself to the search for truth, realizing this will be an unending quest that will require all things to be questioned. You begin the lifelong implementation of this decision by reconciling yourself to everything you currently know.
Once you are in the gate, you begin walking the narrow path. In scriptural terms, you:
...press forward with a steadfastness in Christ, having a perfect brightness of hope, and a love of God and of all men. Wherefore, if ye shall press forward, feasting upon the word of Christ, and endure to the end, behold, thus saith the Father: Ye shall have eternal life. (2 Nephi 31:20)
In plain terms, you diligently search for more truth, and continue reconciling yourself to everything you learn, and eventually you will acquire all the knowledge required for eternal life.
If the description of the narrow gate and narrow way are so simple (continuously search for truth and keep yourself reconciled to it), why do so few find it? Why are so few “chosen”?
The Lord said:
35 Because their hearts are set so much upon the things of this world, and aspire to the honors of men, that they do not learn this one lesson—
36 That...the powers of heaven cannot be controlled nor handled only upon the principles of righteousness.
37 That [when they deviate from this] the heavens withdraw themselves; the Spirit of the Lord is grieved....
38 Behold, ere he is aware, he is left unto himself, to kick against the pricks, to persecute the saints, and to fight against God. (D&C 121)
It is rare to enter into the narrow path and difficult to remain on the narrow way because we prefer the illusion of the things as the world shows us or as we wish they were to things as they really are.
When we act contrary to our sincere understanding of what is good, we lose light. “And that wicked one cometh and taketh away light and truth, through disobedience, from the children of men, and because of the tradition of their fathers.” (D&C 93:39) We are removed from the narrow path and start back outside the narrow gate. We are exposed to the consequences of our acting against reality, and will remain subject to those consequences until we submit to the search of truth and sincere reconciliation to our understanding of what is good.