Elder Dallin H. Oaks of the Quorum of the Twelve Apostles discussed how a hard heart limits our spirituality:
“Nephi attempted to teach his brothers that they could know the meaning of their father’s prophetic utterances, ‘which were hard to be understood, save a man should inquire of the Lord’ (1 Ne. 15:3). Nephi told them if they did not harden their hearts and would keep the commandments and inquire of the Lord in faith, ‘surely these things shall be made known unto you’ (1 Ne. 15:11).
“If we harden our hearts, reject continuing revelation, and limit our learning to what we can obtain by study and reason on the precise language of the present canon of scriptures, our understanding will be limited to what Alma called ‘the lesser portion of the word’ (Alma 12:11). If we seek and accept revelation and inspiration to enlarge our understanding of the scriptures, we will realize a fulfillment of Nephi’s inspired promise that those who diligently seek will have ‘the mysteries of God … unfolded unto them, by the power of the Holy Ghost’ (1 Ne. 10:19)” (“Scripture Reading and Revelation,” Ensign, Jan. 1995, 7).
The Prophet Joseph Smith explained that not only could Laman and Lemuel know the things Nephi and his father knew, but that this principle applies to us as well: “Could we all come together with one heart and one mind in perfect faith the veil might as well be rent today as next week, or any other time” (Teachings of the Prophet Joseph Smith, sel. Joseph Fielding Smith [1976], 9).
“God hath not revealed anything to Joseph, but what He will make known unto the Twelve, and even the least Saint may know all things as fast as he is able to bear them” (History of the Church, 3:380).