The same came to him by night, and said to him, "Rabbi, we know that you are a teacher come from God, for no one can do these signs that you do, unless God is with him."

 When Nicodemus came to Jesus, he said that no one could help being impressed with the signs and wonders that he did. Jesus' answer was that it was not the signs and the wonders that were really important; the important thing was such a change in a man's inner life that it could only be described as a new birth. 