Alma 13

As Alma taught the people of Ammonihah concerning having received the priesthood in our pre-mortal existence he said -

"...thus they have been called to this holy calling on account of their faith, while others would reject the Spirit of God on account of the hardness of their hearts and blindness of their minds, while, if it had not been for this they might have had as great privilege as their brethren.
5 Or in fine, in the first place they were on the same standing with their brethren; thus this holy calling being prepared from the foundation of the world for such as would not harden their hearts, being in and through the atonement of the Only Begotten Son, who was prepared—" (Book of Mormon | Alma 13:4 - 5)

We learn that in our pre-mortal existence, we were born as spirit offspring being "on the same standing" or in other words being equal in opportunity or right to choose righteousness and pursue happiness or to do that of hardening our hearts. Those that were found worthy were "called to this holy calling" or ordained because of faithfulness. The same pattern we find in this life. But there is one more very important essential doctrine that Alma taught, again -

"...being prepared from the foundation of the world for such as would not harden their hearts, being in and through the atonement of the Only Begotten Son..." (Book of Mormon | Alma 13:5)

Those words in themselves suggest follows the teaching that the atonement is "an infinite atonement" meaning that it's power and blessings extended from the foundation of the world or in other words, it's power and blessings exercised in the pre-mortal existence. The doctrine of faith and repentance was practice there. Elder Jeffrey R. Holland said -

"...that even in the Grand Council of Heaven he loved us and was wonderfully strong, that we triumphed even there by the power of Christ and our faith in the blood of the Lamb (see Rev. 12:10–11)."

We find it a truth in the Lord said -

"...I will give unto you a pattern in all things, that ye may not be deceived..." (Doctrine and Covenants | Section 52:14)