What . . . is this testimony of Jesus, how can it be acquired, and what will it do for those who receive it? The testimony of Jesus is the sure and certain knowledge, revealed to the spirit of a person through the Holy Ghost, that Jesus is the living Son of the living God. Because the testimony of Jesus is God-given, it stands preeminent and is essential to a happy life. It is the fundamental principle of our religion, and all other things pertaining to our faith are appendages to it.