The gospel of the Lord Jesus Christ advises men to test its truths in human life. It approves distinctly of the experimental method. The Savior laid down the principle in a luminous statement: ‘My doctrine is not mine, but his that sent me. 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 7:16, 17)
On another occasion He repeated the thought: ‘If I do not the works of my Father, believe me not. But if I do, though ye believe not me, believe the works.’ (John 10:37, 38) The words of the Apostle Paul, ‘Prove all things; hold fast that which is good.’ (1 Thessalonians 5:21), are of the same import. There is constant advice in the scriptures to let the effects of gospel living be evidence of its truth, as for example:
‘Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven’
(Matthew 5:16)
‘Having your conversation honest among the Gentiles: that, whereas they speak against you as evil-doers, they may by your good works, which they shall behold, glorify God in the day of visitation.’
(1 Peter 2:12)
Joseph Smith, the Prophet, recognized this method of testing truth. He read the words of James, ‘If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him’ (James 1:5); and, believing in God, he went into the grove to test the reality of the promise there made. Thus came the great First Vision.
(John A. Widtsoe, Evidences and Reconciliations, pp. 26–27)