Matthew 17:18

Verse 18. Why could not we? The disciples began to apprehend that they had incurred their Master’s displeasure, and had thereby lost their power of working miracles. They come therefore secretly to Jesus Christ, to learn why they could not cast out devils. He answered them, that it was their want of faith, which probably failed them on this occasion, on account of the difficulty of the cure, little reflecting that the virtue of the Lord, which worked in them, was superior to every possible evil of both mind and body.—S. Hilary is of opinion, that during the absence of Christ on the mountain, the fervour of the apostles had begun to abate. Jans.