So glorious is the Savior’s message of truth that Mormon is allowed to share but a small part of it (see 3 Nephi 26:6). He is restrained from bringing more into view, since the Savior declares: “I will try the faith of my people” (3 Nephi 26:11). The “more part” (3 Nephi 26:7) of the repository of unspeakable truth from the Savior’s visit is left sealed upon the plates of Nephi until a later time when the faith of the people merits an expanded account of this singularly important occasion.
We are to be tested here upon the earth. This is why Mormon is instructed to withhold some of the teachings and manifestations that are received at the time of the coming of our Savior. Part of the test of life has to do with our ability to acquire and exercise faith in the Lord Jesus Christ. There is often no witness until after the trial of our faith (see Ether 12:6). We, like the Apostles of old, seek the help of the Lord so that our faith might be increased (see Luke 17:5). We fast and pray for our faith to be firm (see Helaman 3:35). We feast on and hearken to the word of God so that our faith will be increased (see Romans 10:17). We recognize that our faith will only work as we are full of love (see Galatians 5:6). The true test of our faith is whether or not we believe and accept the word of God and act accordingly. In other words, we will show our faith by our works (see James 2:17–26). Remember that it is impossible to please God without faith (see Hebrews 11:6), for faith is the foundation of all righteousness.
We are here to be tested (see Abraham 3:25). We please God with our faith (see Hebrews 11:6). It is faith for which we plead (see Luke 17:5). Through searching and hearing the word (see Romans 10:17) and praying with all our heart (see Helaman 3:35) our faith will increase (see Lectures on Faith [Salt Lake City: Deseret Book, 1985], 1:1).
The amount of knowledge we receive is really dependant upon us. Scholar Larry E. Dahl provides this explanation:
Many factors influence how much God reveals, to whom, and under what circumstances. These include (1) who takes the opportunity to ask the Father in the name of Christ; (2) how much faith those seeking knowledge have; (3) what they ask for; (4) what is good for them to receive (D&C 18:18); (5) how willing they are to obey what is given (Alma 12:9–11); (6) what the will and wisdom of God require, for he gives “all that he seeth fit that they should have” (Alma 29:8); (7) whether the faith of people needs to be tested (Mormon was about to write more, but “the Lord forbade it, saying: I will try the faith of my people” [3 Nephi 26:9; 3 Nephi 26:8–11]); and (8) how spiritually prepared people are to receive the revelation (for example, Jesus taught through parables in order to protect those who were not ready to understand [Luke 8:10; D&C 19:22]). The eternal truths constituting the gospel do not change, and eventually all who are exalted in the kingdom of God will understand them and apply them fully. However, mankind’s knowledge and understanding of these truths change, as do the policies and practices appropriate to concurrent levels of understanding and obedience.” (Encyclopedia of Mormonism, 1–4 vols., ed. Daniel H. Ludlow (New York: Macmillan, 1992), 395)