And we believe and are sure
Or know of a certainty: they believed upon the first call of them by Christ, and their following of him, that he was the true Messiah; and they came to an assurance of it, by the miracles he wrought, and by the doctrines which he taught; their faith, how weak soever it might be at first, rose up to a full assurance of faith, and of understanding; there was a reality and a certainty in it, as there is in all true faith, with respect to the object, though not always with respect to interest in it; which was the case here, as appears by what follows:
that thou art that Christ;
or Messiah, that was promised by God of old, spoken of by the prophets, and expected by the Jews; that anointed prophet Moses had spoken of, that should arise out of Israel, like unto him that anointed priest, who, according to the oath of God, was to be priest for ever, after the order of Melchizedek; and that anointed King, whom God has set over his holy hill of Zion:
the son of the living God;
this they knew, and were sure of, both by John's testimony, and by the father's voice from heaven; which three of them heard, at Christ's transfiguration on the mount: God the father is called "the living God"; though the Vulgate Latin version leaves out the word "living"; not to distinguish him from his son; for he also is the living God; and is so called, ( Hebrews 3:12 ) , but to distinguish him from the idols of the Gentiles, who have no life nor breath in them: and Christ is called the son of the living God, as he is a divine person, as he is truly God; and to show that he has the same life his father has; being a partaker of the same nature, and divine perfections: and this is another reason why sensible souls will go to Christ, and no other; because he is the Messiah, the Saviour, and Redeemer, and an able one; and because he is God, and there is none else.