Jesus heard that they had east him out; or, thrust him forth. Jesus is represented as "hearing," not from the man's own lips, but from the current report. He is not said to have become acquainted with the circumstance by intuition, but to have heard by the ordinary processes of knowledge.
This simple touch shows how consistent the writer is throughout with the main thesis of his Gospel touching the perfect humanity of the Son of God, that he "was made flesh." and had "come in the flesh," though he was "from God."
The excommunication noisily and widely bruited was further proof of the war to the knife between "the Jews" and Jesus. The man has fallen under the ban for practically avowing in the most public way that Jesus was "the Prophet," if not the Christ.
And having found him. So, then, the Lord, as the good Shepherd, sought out the lost sheep in the wilderness, and did not rest until he found him. The daylight that had made an altogether new world for one who had aforetime never looked on human face, had been strangely checkered and shadowed.
He only saw angry faces and averted glances, and even his cowardly parents would have hesitated to receive him into their poor abode; but Jesus found him, and said, Dost thou believe on the £ Son of God?
Not "Dost thou wish to believe?" but "Dost thou put thy trust in the Son of God?" Dost thou recognize the fact that the Messiah of the nation's hope has come? Art thou believing in him? It would be more natural that the more current appellation Son of God, rather than the more recondite idea of Son of man, should have been held out before the healed man.
The "thou" is emphatic, and contrasts the state of the mind of this man with that of "the Jews." He had declared that his Healer was "from God," that he was "a Prophet," One who "did God's will," and whom "God heareth," even when he asked for apparently impossible things.
Christ tests the quality and caliber of his faith.