On the character of Nicodemus, see Notes on John 3. His position here is that of a friend of Jesus, who still does not dare to declare himself His open follower.
He that came to Jesus by night. — Comp. Note on John 3:2. The better reading here is, probably, he that came to Him before.
Being one of them contains the answer to their question, “Hath any one (as above) of the rulers or of the Pharisees believed on Him?” (John 7:48).