The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him. Came to Jesus by night - He had matters of the utmost importance, on which he wished to consult Christ; and he chose the night season, perhaps less through the fear of man than through a desire to have Jesus alone, as he found him all the day encompassed with the multitude; so that it was impossible for him to get an opportunity to speak fully on those weighty affairs concerning which he intended to consult him. However, we may take it for granted that he had no design at present to become his disciple; as baptism and circumcision, which were the initiating ordinances among the Jews, were never administered in the night time. If any person received baptism by night, he was not acknowledged for a proselyte. See Wetstein. But as Jews were not obliged to be baptized, they being circumcised, and consequently in the covenant, he, being a Jew, would not feel any necessity of submitting to this rite.
Rabbi - My Master, or Teacher, a title of respect given to the Jewish doctors, something like our Doctor of Divinity, i.e. teacher of Divine things. But as there may be many found among us who, though they bear the title, are no teachers, so it was among the Jews; and perhaps it was in reference to this that Nicodemus uses the word διδασκαλος, didaskalos, immediately after, by which, in John 1:38, St. John translates the word rabbi. Rabbi, teacher, is often no more than a title of respect: didaskolos signifies a person who not only has the name of teacher, but who actually does teach.
We know that thou art a teacher come from God - We, all the members of the grand Sanhedrin, and all the rulers of the people, who have paid proper attention to thy doctrine and miracles. We are all convinced of this, though we are not all candid enough to own it. It is possible, however, that οιδαμεν, we know, signifies no more than, it is known, it is generally acknowledged and allowed, that thou art a teacher come from God.
No man can do these miracles - It is on the evidence of thy miracles that I ground my opinion of thee. No man can do what thou dost, unless the omnipotence of God be with him.