Now there was a man of the Pharisees named Nicodemus, a ruler of the Jews.
Rabbi, we know that thou art a teacher come from God ...  The words "we know" indicate the profound effect which the mighty signs of Jesus had produced in the very center of Judaism.  These words admit that the whole Sanhedrin knew of the heavenly origin of Jesus and of the validity of his astounding miracles.  Only one of the great signs John selected for this Gospel had been recorded at this point; but Nicodemus' words, along with  John 2:23, show that many signs had been wrought.