If any man will do his will

“If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself” (John 7:17).

Action—an exercise of agency to choose to follow Christ—is what builds faith and leads to spiritual knowledge. Actually doing God's will is the only way we can obtain a witness, an assurance, a testimony, a knowledge of spiritual truths.

Spiritual experiences and miracles strengthen faith in those who already have faith, and sometimes invite actions in those with little or no faith that will lead them to belief and faith, but in the long run miraculous experiences do not have the staying power that simple obedience to covenants (or to the commitments that will lead to covenants) has.

That is one reason, among others, that missionaries (who are out there inviting people to come unto Christ) and priesthood leaders (who are ministering to the spiritual needs of those who have already come unto Christ through faith, repentance, and baptism) are always inviting people to do things. Our responding to such invitations is what gives us spiritual insight, knowledge, and power.