13 Come unto me, O ye Gentiles, and I will show unto you the greater things, the knowledge which is hid up because of unbelief.
14 Come unto me, O ye house of Israel, and it shall be made manifest unto you how great things the Father hath laid up for you, from the foundation of the world; and it hath not come unto you, because of unbelief.
15 Behold, when ye shall rend that veil of unbelief which doth cause you to remain in your awful state of wickedness, and hardness of heart, and blindness of mind, then shall the great and marvelous things which have been hid up from the foundation of the world from you–yea, when ye shall call upon the Father in my name, with a broken heart and a contrite spirit, then shall ye know that the Father hath remembered the covenant which he made unto your fathers, O house of Israel.
As Moroni ends his discussion of the brother of Jared’s supernal experience, he delivers a promise from the Savior to us: if we will overcome our unbelief, we also can gain great spiritual knowledge. Belief is a prerequisite for spiritual understanding.
Before showing Himself to the brother of Jared, the Savior asked, “Believest thou the words which I shall speak?” The brother of Jared did not know what the Lord was about to say, but he answered, “Yea, Lord, I know that thou speakest the truth, for thou art a God of truth, and canst not lie” (Ether 3:11-12). After this expression of faith, the Lord showed Himself to the brother of Jared and then showed him all the inhabitants of the world. Moroni tells us that the Lord had promised the brother of Jared previously “that if he would believe in him that he could show unto him all things…therefore the Lord could not withhold anything from him” (Ether 3:26).
Similarly, when Nephi prayed to see the things his father had seen, he was asked, “Believest thou that thy father saw the tree of which he hath spoken?” (1 Nephi 11:4) Only after His affirmative response was the vision given to him. His brothers, who complained about their lack of knowledge but didn’t make the effort to know for themselves, didn’t gain the same understanding. (1 Nephi 15:2-9) The knowledge was hidden from them because of their unbelief.
Boyd K. Packer encouraged young missionaries to bear testimony of the things that they want to know. He promised that, as they spoke the truth with faith, the Holy Ghost would ratify the truths they had just spoken. Without that act of faith, they might never come to know for themselves that the gospel is true:
Somewhere in your quest for spiritual knowledge, there is that “leap of faith,” as the philosophers call it. It is the moment when you have gone to the edge of the light and stepped into the darkness to discover that the way is lighted ahead for just a footstep or two. “The spirit of man,” is as the scripture says, indeed “is the candle of the Lord.” (Prov. 20:27.) (“The Candle of the Lord,” Ensign, January 1983)
Today I will choose to believe. As I seek greater spiritual knowledge, I will begin by affirming the things I know to be true. I will remember that the process of acquiring spiritual knowledge requires me first to “rend that veil of unbelief.”