Mark 9:18

This saying, If thou canst, is a proof of the freedom of the will. Again, all things are possible to him that believeth, which evidently means all those things which are prayed for with tears in the name of Jesus, that is, of salvation. By this also we are taught that our faith is tottering, if it lean not on the stay of the help of God. But faith by its tears receives the accomplishment of its wishes; Wherefore it continues, When Jesus saw that the multitude came running together, he rebuked the foul spirit, saying unto him, Thou dumb and deaf spirit, I charge thee come out of him, and enter no more into him. Again, a sinner foameth forth folly, gnasheth with anger, pineth away in sloth. But the evil spirit tears him, when coming to salvation, and in like manner those whom he would drag into his maw he tears asunder by terrors and losses, as he did Job. Further, in his being vexed from his infancy, the Gentile people is signified, from the very birth of whom the vain worship of idols arose, so that they in their folly sacrificed their children to devils. And for this reason it is said that it cast him into the fire and into the water; for some of the Gentiles worshipped fire, others water. Again, the Lord applies to the evil spirit what he had inflicted on the man, calling him deaf and dumb spirit, because he never will hear and speak what the penitent sinner can speak and hear. But the devil, quitting a man, never returns, if the man keep his heart with the keys of humility and charity, and hold possession of the gate of freedom.1 The man who was healed became as one dead, for it is said to those who are healed, Ye are dead, and your life is hid with Christ in God. (Col. 3:3.)

(ubi sup.) The Scriptures declare that this man was weak in faith, for Christ says, O faithless generation: and He adds, If thou canst believe. But although his want of faith was the cause of their not casting out the devil, he nevertheless accuses the disciples; wherefore it is added, And I spake to thy disciples that they should cast him out; but they could not. Now observe his folly; in praying to Jesus in the midst of the crowd, he accuses the disciples, wherefore the Lord before the multitude so much the more accuses him, and not only aims the accusation at himself, but also extends it to all the Jews; for it is probable that many of those present had been offended, and had held wrong thoughts concerning His disciples. Wherefore there follows, He answereth them and saith, O faithless generation, how long shall I be with you? how long shall I suffer you? By which He showed both that He desired death, and that it was a burden to Him to converse with them.

(ubi sup.) The question, indeed, which was raised may, if I am not deceived, have been this, wherefore they, who were the disciples of the Saviour, were unable to heal the demoniac, who was placed in the midst, which may be gathered from the following words; And one of the multitude answered and said, Master, I have brought unto thee my son, which hath a dumb spirit; and wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away.