Mosiah 3

As King Benjamin continued to speak to his people, he makes an interesting point -

"...men drink damnation to their own souls except they humble themselves and become as little children, and believe that salvation was, and is, and is to come, in and through the atoning blood of Christ, the Lord Omnipotent.
19 For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord, and becometh as a child, submissive, meek, humble, patient, full of love, willing to submit to all things which the Lord seeth fit to inflict upon him, even as a child doth submit to his father." (Book of Mormon | Mosiah 3:18 - 19)

First, it becomes clear that men are not born as a "natural man". We are born as children, "submissive, meek, humble, patient, full of love, willing to submit" to our parents. It is as we grow and use are agency that men become natural men. Enoch taught this same doctrine explaining that -

"...Satan hath come among the children of men, and tempteth them to worship him; and men have become carnal, sensual, and devilish, and are shut out from the presence of God." (Pearl of Great Price | Moses 6:49)

King Benjamin explains the key in not becomeing "carnal, sensual, and devilish" or in other words, the "natural man" in that -

"...he yields to the enticings of the Holy Spirit..."(Book of Mormon | Mosiah 3:19)

As his people -

"...viewed themselves in their own carnal state, even less than the dust of the earth. And they all cried aloud with one voice, saying: O have mercy, and apply the atoning blood of Christ that we may receive forgiveness of our sins, and our hearts may be purified; for we believe in Jesus Christ, the Son of God..." (Book of Mormon | Mosiah 4:2)

"...the Spirit of the Lord came upon them, and they were filled with joy, having received a remission of their sins, and having peace of conscience..." (Book of Mormon | Mosiah 4:3)

And thus they became as little children "willing to submit to all things which the Lord seeth fit to inflict upon him" -

"...because of the Spirit of the Lord Omnipotent, which has wrought a mighty change in us, or in our hearts, that we have no more disposition to do evil, but to do good continually." (Book of Mormon | Mosiah 5:2)

The key is to receive the Holy Ghost.