Yea, he that repenteth and exerciseth faith, and bringeth forth good works, and prayeth continually without ceasing—unto such it is given to know the mysteries of God; yea, unto such it shall be given to reveal things which never have been revealed; yea, and it shall be given unto such to bring thousands of souls to repentance, even as it has been given unto us to bring these our brethren to repentance.

https://www.lds.org/scriptures/bofm/alma/26.11-12