The Bible says that to let everything be established at the mouth of two or three witnesses. http://ref.ly/Dt19.15 Jesus’ first witness is John the Baptist. Jesus’ next witness is the works the Father wants Him to finish. These works are a better witness that John’s words. They are a manifestation of the words that Jesus speaks. The Father Himself sent Jesus and bears witness of Jesus. There are Jesus’ three witnesses! This requirement of the law was fulfilled.
Jesus then makes a scathing accusation by saying that the Word of God is not abiding in those who hear His voice. This is a pointed statement toward the religious leaders of that day. If they had the Old Testament residing in their lives, then they would have believed in Jesus! What a statement!