Matthew 17:19-21

Ver 19. Then came the disciples to Jesus apart, and said, "Why could not we cast him out?" 20. And Jesus said unto them, "Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. 21. Howbeit this kind goeth not out but by prayer and fasting."

Chrys.: The disciples had received from the Lord the power over unclean spirits, and when they could not heal the daemoniac thus brought to them, they seem to have had misgivings lest they had forfeited the grace once given to them; hence their question. And they ask it apart, not out of shame, but because of the unspeakable matter of which they were to ask. "Jesus said unto them, Because of your unbelief."

Hilary: The Apostles had believed, yet their faith was imperfect; while the Lord tarried in the mount, and they abode below with the multitude, their faith had become stagnant.

Chrys.: Whence it is plain that the disciples' faith was grown weak, yet not all, for those pillars were there, Peter, and James, and John.

Jerome: This is what the Lord says in another place, "Whatsoever ye shall ask in my name believing, ye shall receive." [Matthew 21:22; John 16:23] Therefore when we receive not, it is not the weakness of Him that gives, but the fault of them that ask.

Chrys.: But it is to be known, that, as ofttimes the faith of him that draweth near to receive supplies the miraculous virtue, so ofttimes the power of those that work the miracle is sufficient even without the faith of those who sought to receive. Cornelius and his household, by their faith, attracted to them the grace of the Holy Spirit [Acts 10:4]; but the dead man who was cast into the sepulchre was revived solely by virtue of the holy body. [2 Kings 13:21]

It happened that the disciples were then weak in faith; for indeed they were but in an imperfect condition before the cross; wherefore He here tells them, that faith is the mean of miracles, "Verily I say unto you, if ye shall have faith as a grain of mustard-seed, ye shall say to this mountain, Remove hence, and it shall remove."

Jerome: Some think that the faith that is compared to a grain of mustard-seed is a little faith, whereas the Apostle says, "If I shall have such faith that I could remove mountains." [1 Corinthians 13:2] The faith therefore which is compared to a grain of mustard-seed is a great faith.

Greg., Mor., pref. c. 2: The mustard-seed, unless it be bruised, does not give out its qualities, so if persecution fall upon a holy man, straightway what had seemed weak and contemptible in him is roused into the heat and fervour of virtue.

Origen: Or, all faith is likened to a grain of mustard-seed, because faith is looked on with contempt by men, and shews as something poor and mean; but when a seed of this kind lights upon a good heart as its soil, it becomes a great tree. The weakness of this lunatic's faith is yet so great, and Christ is so strong to heal him amidst all his evils, that He likens it to a mountain which cannot be cast out but by the whole faith of him who desires to heal afflictions of this sort.

Chrys.: So He not only promises the removal of mountains, but goes beyond, saying, "And nothing shall be impossible to you."

Raban.: For faith gives our minds such a capacity for the heavenly gifts, that whatsoever we will we may easily obtain from a faithful Master.

Chrys.: If you shall ask, Where did the Apostles remove mountains! I answer, that they did greater things, bringing many dead to life. It is told also of some saints, who came after the Apostles, that they have in urgent necessity removed mountains. [ed. note: St. Augustine says, that he had never read or heard of a mountain being transported into the sea by faith. Sp. et lit. n. 62. St. Chrysostom appears to refer to the occurrence recorded in the history of Gregory of Neo-Caesarea, called Thaumaturgus, A.D. 260, whose miracles are reported to us by his namesake of Nyssa. Nyssen, however, speaks only of his moving a stone, (vol. ii. p. 982.) Pope Gregory, Dial. i. 7. calls it a rock, or even a mountain. He mentions it while relating the like miracle in the history of St. Benedict. In volcanic countries, changes in mountains and rivers occur even from natural causes, much more might prayer cause them. But St. Augustine's remark shews that there is very little evidence for the fact.]

But if mountains were not removed in the Apostles' time, this was not because they could not, but because they would not, there being no pressing occasion. And the Lord said not that they should do this thing, but that they should have power to do it.

Yet it is likely that they did do this, but that it is not written, for indeed not all the miracles that they wrought are written.

Jerome: Or; the mountain is not said of that which we see with the eyes of the body, but signified that spirit which was removed by the Lord out of the lunatic, who is said by the Prophet to be the corrupter of the whole earth

Gloss. interlin.: So that the sense then is, "Ye shall say to this mountain," that is to the proud devil, "Remove hence," that is from the possessed body into the sea, that is into the depths of hell, "and it shall remove, and nothing shall be impossible to you," that is, no sickness shall be incurable."

Aug.: Otherwise; That the disciples in working their miracles should not be lifted up with pride, they are warned rather by the humbleness of their faith, as by a grain of mustard-seed, to take care that they remove all pride of earth, which is signified by the mountain in this place.

Raban.: But while He teaches the Apostles how the daemon ought to be cast out, He instructs all in regulation of life; that we may all know that all the heavier afflictions, whether of unclean spirits, or temptations of men, may be removed by fasts and prayers; and that the wrath also of the Lord may be appeased by this remedy alone; whence he adds, "Howbeit this kind is not cast out but by prayer and fasting."

Chrys.: And this He says not of lunatics in particular, but of the whole class of daemons. For fast endues with great wisdom, makes a man as an Angel from heaven, and beats down the unseen powers of evil. But there is need of prayer as even still more important. And who prays as he ought, and fasts, had need of little more, and so is not covetous, but ready to almsgiving. For he who fasts, is light and active, and prays wakefully, and quenches his evil lusts, makes God propitious, and humbles his proud stomach. And he who prays with his fasting, has two wings, lighter than the winds themselves. For he is not heavy and wandering in his prayers, (as is the case with many,) but his zeal is as the warmth of fire, and his constancy as the firmness of the earth. Such an one is most able to contend with daemons, for there is nothing more powerful than a man who prays properly.

But if your health be too weak for strict fast, yet is it not for prayer, and if you cannot fast, you can abstain from indulgences. And this is not a little, and not very different from fast.

Origen: If then we shall ever be required to be employed in the healing of those who are suffering any thing of this sort, we shall not adjure them, nor ask them questions, nor even speak, as though the unclean spirit could hear us, but by our fasting and our prayers drive away the evil spirits.

Gloss. ord.: Or; This class of daemons, that is the variety of carnal pleasures, is not overcome unless the spirit be strengthened by prayer, and the flesh enfeebled by fast.

Remig.: Or, fasting is here understood generally as abstinence not from food only, but from all carnal allurements, and sinful passions. In like manner prayer is to be understood in general as consisting in pious and good acts, concerning which the Apostle speaks, "Pray without ceasing." [1 Thessalonians 5:17]