and because he didn't need for anyone to testify concerning man; for he himself knew what was in man.

 Jesus' reply constitutes the great problem of this passage. What did he really say? And what did he really mean? It is always to be remembered that John 2:21-22 are John's interpretation written long afterwards. He was inevitably reading into the passage ideas which were the product of seventy years of thinking about and experience of the Risen Christ. As Irenaeus said long ago: "No prophecy is fully understood until after the fulfilment of it." But what did Jesus originally say and what did he originally mean? 