When Pilate asked Jesus, “What is truth?” Pilate told the Jews he was satisfied with his answer and could “find in him no fault at all.” (John 18:38) Jesus had already answered this question for His disciples: “I am the way, the truth, and the life. No man cometh unto the Father, but by me.” (John 14:6) The early followers of Jesus called the Christian movement, “The Way.” Jesus is the way back to the Father and the greatest of all the gifts of God — Eternal Life. (highlights mine)
He extended the great promise, “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) In other words, if we live the doctrine He is teaching, we can know it is true by the fruits. Wherefore by their fruits, ye shall know them.” (Luke 6:43-44)