Nathanael answered and said unto him, Rabbi, you are the Son of God; you are the King of Israel.
All Commentaries on John 1:49 Go To John 1
Cyril of Alexandria
AD 444
He knows that God Alone is Searcher of hearts, and giveth to none other of men to understand the mind, considering as is likely that verse in the Psalms, God trieth the hearts and reins. For as accruing to none else, the Psalmist hath attributed this too as peculiar to the Divine Nature only. When then he knew that the Lord saw his thoughts revolving in his mind in yet voiceless whispers, straightway he calls Him Master, readily entering already into discipleship under Him, and confesses Him Son of God and King of Israel, in Whom are inexistent the Properties of Divinity, and as one well instructed he affirms Him to be wholly and by Nature God.