3 Nephi 21:22

But if they will repent and hearken unto my words, and harden not their hearts, I will establish my church among them, and they shall come in unto the covenant and be numbered among this the remnant of Jacob, unto whom I have given this land for their inheritance;

This prophecy is about those who accept the gospel and enter into the covenants of baptism and the temple. We are added to the Lord's chosen people because of our covenants, regardless of our birth heritage or DNA. We therefore share in the inheritance of the promised land with the rest of Lehi's descendants. The same is true of our spiritual homeland. We can be accepted into the celestial kingdom because of covenants, and because of the covenant Christ made with the Father to be our Redeemer, Mediator, and Savior.

3 Nephi 12:26

Verily, verily, I say unto thee, thou shalt by no means come out thence until thou hast paid the uttermost senine. And while ye are in prison can ye pay even one senine? Verily, verily, I say unto you, Nay.

We are faced with a troubling paradox: we cannot get out of prison unless we pay the fine, yet we cannot pay the fine while we are in prison. What is the solution? Someone else must pay the fine for us. We cannot redeem ourselves. We need a mediator. Jesus Christ is our Redeemer.