John Calvin Commentary Matthew 12:23

"And all the multitudes were amazed, and said, Can this be the son of David?" — Matthew 12:23 (ASV)

And all the people were astonished. From this we infer that there was a visible display of God's power, which drew to him the admiration of the great number of the people, who were not at all motivated by any wicked disposition. For how did it happen that everyone admired it, if not because the event itself compelled them to do so? And certainly, not one of us fails to see in this narrative, as in a mirror, an unusual power of God. Therefore, it follows that a devilish poison must have seized the minds of the scribes, who were not ashamed to slander so remarkable a work of God.

But we must attend to the result of the miracle. Moved with admiration, those who saw it ask each other, Is not Jesus the Christ? Acknowledging God's power, they are led, as it were by the hand, to faith.

Not that they suddenly progressed as much as they should have (for they speak doubtfully); but it is still no small progress to be aroused to consider Christ's glory more attentively. Some regard this as a full affirmation, but the words convey no such meaning. The event itself shows that an unexpected occurrence had struck them forcibly, and that they did not form a decided opinion, but only that it occurred to them that he might be the Christ.