“To Know and to Really Know,” Ensign, Mar. 1980, 59
When we lived with our Father in heaven, we did not need to exercise faith in whether or not he existed. We knew that he was because we saw him; we walked and talked with him. We were convinced of his existence, but we were not necessarily converted to him and to his teachings because our knowledge of him had come from external sources with virtually no effort on our part.
So that we would come to a knowledge of him in and of ourselves, our Heavenly Father proposed that when we came into this earth life a veil of forgetfulness would be placed over our minds so that we would not remember our pre-earthly existence with him. Only then could the choices that we made here upon this earth truly come from within us. Our Father in heaven then promised us that while we were here on the earth he would give us laws, would provide the possibility of opposites, would give us free agency, and would send angels and prophets to teach us and give us scriptures so we could learn the laws and the reasons why we should keep them. Thus, he promised us the necessary conditions on this earth wherein we could become morally free before him. …
It was explained in this great pre-earthly council that as we would come to the earth the Spirit of Christ would be placed within each of us and that another member of the Godhead, the Holy Ghost, would be empowered to witness, reveal, and testify to our spirits. Then, even though we had a veil of mortality over our minds, the Holy Ghost would be able to bring all things to our remembrance if we would listen to the words of the prophets, would read the words of the scriptures, and would respond to the Spirit of Christ within us by praying to our Father in heaven. This time, however, the knowledge would come to us by an act of will on our part. We would have internalized it; it would have become part of our very being, and therefore no one throughout all eternity could take this knowledge away from us unless we, by an act of will on our part, would allow this knowledge to be taken away.
Daniel H. Ludlow, Values Institute, Brigham Young University