Jesus answered and said unto him. This weighty and momentous answer is given alone by St. Matthew. St. Mark, who wrote under the instruction of Peter, and for Roman Christians, mentions it not; the other two evangelists are equally silent, having evidently not understood the special importance attached to it.
Blessed art thou, Simon Bar-jona. "Blessed," as in the sermon on the mount (Mark 5:1-43.), expressing a solemn benediction, not a mere encomium. Peter was highly favoured by a special revelation from God.
Christ calls him "son of Jona," to intimate that Peter's confession is true—that he himself is as naturally and truly Son of God as Peter is son of Jona. So Christ addresses him when he restores the fallen apostle at the Sea of Galilee after the second miraculous draught of fishes, reminding him of his frail human nature in the face of great spiritual privileges (John 21:15, etc.
; comp. Matthew 1:1-25:42). Simon would be the name given at his circumcision; Bar-jona, a patronymic to distinguish him from others of the same name. For ( ὅτι). This introduces the reason why Christ calls him "Blessed."
Flesh and blood. This is a phrase to express the idea of the natural man, with his natural endowments and faculties. So St. Paul says (Galatians 1:16), "I conferred not with flesh and blood;" and "Our wrestling is not against flesh and blood" (Ephesians 6:12).
The Son of Sirach speaks of "the generation of flesh and blood" (Ecclesiasticus 14:18). No natural sagacity, study, or discernment had revealed the great truth. None of these had overcome slowness of apprehension, prejudices of education, slackness of faith.
No unregenerate mortal man had taught him the gospel mystery. My Father which is in heaven. Christ thus accepts Peter's definition of him as "the Son of the living God." None but the Father could have revealed to thee the Son.