John Calvin Commentary John 9:35

"Jesus heard that they had cast him out; and finding him, he said, Dost thou believe on the Son of God?" — John 9:35 (ASV)

Jesus heard that they had cast him out. From this circumstance, I conjecture that they proceeded to it in a solemn manner, as an affair of great importance. By this example, we are taught how trivial and how little to be dreaded are the excommunications of Christ's enemies. If we are cast out from the assembly where Christ reigns, it is a dreadful judgment executed against us, that we are delivered to Satan (1 Corinthians 5:5), because we are banished from the kingdom of the Son of God. But we are so far from having any reason to dread that tyrannical judgment by which wicked men insult Christ's servants, that, even though no one should drive us out, we ought to flee of our own accord from that place where Christ does not preside by his word and Spirit.

And having found him. If he had been allowed to remain in the synagogue, he would have been in danger of becoming gradually alienated from Christ and plunged into the same destruction as wicked men. Christ now meets him, when he is no longer in the temple but wandering here and there; receives and embraces him, when he is cast out by the priests; raises him up from the ground and offers him life, when he has received the sentence of death. We have known the same thing by experience in our own time. For when Dr. Martin Luther and other similar individuals were beginning to reprove the grosser abuses of the Pope, they scarcely had the slightest taste for pure Christianity; but after the Pope had thundered against them and cast them out of the Roman synagogue by terrifying bulls, Christ stretched out his hand and made himself fully known to them. So, there is nothing better for us than to be at a very great distance from the enemies of the Gospel, so that Christ may draw nearer to us.

Do you believe on the Son of God? He speaks to a Jew who had been instructed from his infancy in the doctrine of the Law and had learned that God had promised the Messiah. This question, therefore, has the same meaning as if Christ had exhorted him to follow the Messiah and to devote himself to him; though he employs a more honorable name than they were accustomed to use at that time, for the Messiah was considered to be only the son of David (Matthew 22:42).