Ether 12: 6
And now, I, Moroni, would speak somewhat concerning these things; I would show unto the world that faith is things which are hoped for and not seen; wherefore, dispute not because ye see not, for ye receive no witness until after the trial of your faith.
:27 And if men come unto me I will show unto them their weakness. I give unto men weakness that they may be humble; and my grace is sufficient for all men that humble themselves before me; for if they humble themselves before me, and have faith in me, then will I make weak things become strong unto them.
Doctrine and Covenants 122:7
7 And if thou shouldst be cast into the pit, or into the hands of murderers, and the sentence of death passed upon thee; if thou be cast into the deep; if the billowing surge conspire against thee; if fierce winds become thine enemy; if the heavens gather blackness, and all the elements combine to hedge up the way; and above all, if the very jaws of hell shall gape open the mouth wide after thee, know thou, my son, that all these things shall give thee experience, and shall be for thy good.