John 1:49 - Matthew Poole's English Annotations on the Holy Bible

The term Rabbi, which Nathanael here giveth to Christ, is of the same significance with Rabban, and Rabboni, 1 Thessalonians 20:16, Rabban, Rabhi, Rabbi, all which signify Master, and my Master; a name which in that age they usually gave their teachers, as a title of honour, Matthew 23:7,8, titles that began about the time of our Saviour; for Buxtorf tells us, purer antiquity gave no such titles to their teachers or prophets, thinking it not possible to give those persons (extraordinarily sent of God) titles answerable to their dignity. They say, Hillel, about our Saviour's time, was the first who was so called; Rabban was counted the highest, Rabbi the next, Rabbi the least. Rabban, they say, lasted about two hundred years, given to seven after Hillel. Nathanael calls him also the Son of God, as Peter and the other disciples did, Matthew 14:33, and Peter, Matthew 16:16. But it appeareth, by many following passages, that they had but a faint persuasion of this, till he was declared so with power, by his resurrection from the dead, Romans 1:4. He acknowledgeth Christ also the King of Israel, that is, the true Messiah. This was the title of the Messiah, Matthew 2:5; Matthew 21:11.