How do we obtain proof?
In the October 2013 General Conference, Elder Jeffrey R. Holland described the pattern we must follow to obtain the Lord's help: "If you had appendicitis, God would expect you to seek a priesthood blessing and get the best medical care available. So too with emotional disorders. Our Father in Heaven expects us to use all of the marvelous gifts He has provided in this glorious dispensation."
For example, if I were to take an examination in school, He will not--indeed, He cannot--help me earn a high grade on the test if I pray for success without first putting forth my honest effort to study the material. He simply will not cheat for me. To learn academic truths, I must humble myself and not only pray but also sacrifice time and effort to read the course material, practice doing problems, and ponder the truths I have learned.
To learn spiritual truths, I must humble myself and sacrifice time to read the scriptures and the words of modern prophets, practice and apply the principles described in those words, and ponder what they mean. In other words, only once I am taking action can I expect Heavenly Father to answer a prayer about whether the things I am reading and learning are true. As President Spencer W. Kimball once said, "You must go to the spiritual laboratory, use the facilities available there, and comply with the governing rules. Then you may know of these truths just as surely, or more surely, than the scientist knows the metals, or the acids, or other elements" ("Absolute Truth", Ensign, Sept. 1978).
For example, how can we know that the Book of Mormon is true? Heavenly Father would expect us to read from the Book of Mormon and then pray to Him and ask Him in prayer what we have read is truth. The more specific our questions are, the more clear the answer will be.