Missionary work important in Nephite nation

The Book of Mormon (Alma 6) reports how missionary work was important
among the Nephite people at the time of Alma. Verses 5 and 6 say,
"Now I would that ye should understand that the word of God was
liberal unto all, that none were deprived of the privilege of
assembling themselves together to hear the word of God. Nevertheless
the children of God were commanded that they should gather themselves
together oft, and join in fasting and mighty prayer in behalf of the
welfare of the souls of those who knew not God." Alma (who had
authority from God) ordained Elders and Priests to watch over and
teach the people of the Church.

Alma speaks about being spiritually born of God

In Alma 5, Alma talks to church members about the need to be spiritually born.

Verse 14 And now behold, I ask of you, my brethren of the church, have
ye spiritually been born of God? Have ye received his image in your
countenances? Have ye experienced this mighty change in your hearts?
Verse 15 Do ye exercise faith in the redemption of him who created
you? Do you look forward with an eye of faith, and view this mortal
body raised in immortality, and this corruption braised in
incorruption, to stand before God to be judged according to the deeds
which have been done in the mortal body?

If we have not been spiritually born of God, we aren't prepared for
the judgment. One characteristics of a person who is spiritually born
of God is humility. Verse 28 says, "Behold, are ye stripped of pride?
I say unto you, if ye are not ye are not prepared to meet God."

Read and listen to Alma 5. http://scriptures.lds.org/en/alma/5