John 1:49 - Ellicott's Commentary On The Whole Bible

Thou art the Son of God. — The recognition begets recognition. That strange Presence he had felt as a spiritual power quickening hope and thought, making prophets’ words living truths, filling with a true meaning the current beliefs about the Messiah; — yes; it goes through and through him again now. It is there before him. “Rabbi, Thou art the Son of God; Thou art the King of Israel.” (For these titles as existing in the Messianic expectation of the day, comp. John 11:27; John 12:13; John 12:15; Matthew 26:63; Mark 3:11; Mark 5:7. See also Note on the quotation from Zech. in Matthew 21:5.)