John Lightfoot on John 3:2

[We know.] It may be a question whether Nicodemus, using the plural number [we know], does by that seem to own that the whole Sanhedrim (of which himself was a member) acknowledge the same thing. I am apt to think the fathers of the Sanhedrim could not well tell how indeed to deny it: which will be more largely discussed upon chapter 11:48. But we know may either be the plural or the singular, which in the first person is most commonly used in all languages. Or else, we know, may signify as much as, it is commonly owned and acknowledged.

[Thou art a teacher come from God.] Nicodemus seems to have reference to the long cessation of prophecy which had not been known in that nation for above four hundred years now past; in which space of time there had been no masters or teachers of the people instituted but by men and the imposition of hands; nor had there in that appeared any one person that would pretend to teach them by a spirit of prophecy:--But we see that thou art a teacher sent from God.