Luther

Certainly, not reason, but the Holy Ghost, must convince people, and He is called the Spirit of truth because He strengthens and upholds the heart against such appearance and feelings. Without Him no man would have believed, or would believe now, that Jesus Christ is true God, sitting eternally at the right hand of the Father, He who was thus shamefully nailed to the cross by His own people, like a thief.—Exposition, John xvi