Jesus replied, “Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven (Matthew 16:17, NIV).
The original of this knowledge is here declared, both negatively and positively. Positively, as God is here declared the author of it. Negatively, as ’tis declared that flesh and blood had not revealed it. God is the author of all knowledge and understanding whatsoever; he is the author of the knowledge that is obtained by human learning; he is the author of all moral prudence, and of the knowledge and skill that men have in their secular business. Thus it is said of all in Israel that were wise-hearted, and skilled in embroidering, that God had filled them with the spirit of wisdom (Exodus 28:3).
God is the author of such knowledge; but yet not so but that flesh and blood reveals it. Mortal men are capable of imparting the knowledge of human arts and sciences, and skill in temporal affairs. God is the author of such knowledge by those means: flesh and blood is made use of by God as the mediate or second cause of it; he conveys it by the power and influence of natural means. But this spiritual knowledge, spoken of in the text, is what God is the author of, and none else: he reveals it, and flesh and blood reveals it not. He imparts this knowledge immediately, not making use of any intermediate natural causes, as he does in other knowledge.
What had passed in the preceding discourse, naturally occasioned Christ to observe this; because the disciples had been telling, how others did not know him, but were generally mistaken about him, and divided and confounded in their opinions of him: but Peter had declared his assured faith that he was the Son of God. Now it was natural to observe, how it was not flesh and blood, that had revealed it to him, but God; for if this knowledge were dependent on natural causes or means, how came it to pass that they, a company of poor fishermen, illiterate men, and persons of low education, attained to the knowledge of the truth; while the scribes and Pharisees, men of vastly higher advantages, and greater knowledge and sagacity in other matters, remained in ignorance? This could be owing only to the gracious distinguishing influence and revelation of the Spirit of God.
Jonathan Edwards, A Divine and Supernatural Light, WJE 17:409-410.