(15) Lunatick.--See Note on Matthew 4:24. The other Gospels add some further touches. The boy had a "dumb spirit." When the spirit seized him it "tore him," and he foamed at the mouth, and gnashed with his teeth. Slowly, and as with difficulty, the paroxysm passed off, and the sufferer was wasting away under the violence of the attacks. The phenomena described are, it need hardly be said, those of epilepsy complicated with insanity, a combination common in all countries, and likely to be aggravated where the "seizure," which the very word epilepsy implies, was the work of a supernatural power. A prolonged melancholy, an indescribable look of sadness, a sudden falling, and loss of consciousness, with or without convulsions, or passing into a tetanic stiffness, a periodical recurrence coinciding often with the new or full moon (hence probably the description of the boy as "lunatick"), grinding the teeth, foaming at the mouth, are all noted by medical writers as symptoms of the disease. The names by which it was known in the earlier stages of medical science were all indicative of the awe with which men looked on it. It was the "divine," the "sacred" disease, as being a direct supernatural infliction. The Latin synonym, morbus comitialis, came from the fact that if a seizure of this kind occurred during the comitia, or assemblies of the Roman Republic, it was looked upon as of such evil omen that the meeting was at once broken up, and all business adjourned. Whether there was in this case something more than disease, viz., a distinct possession by a supernatural force, is a question which belongs to the general subject of the "demoniacs" of the Gospel records. (See Note on 8:28.) Here, at any rate, our Lord's words (Matthew 17:21) assume, even more emphatically than elsewhere, the reality of the possession. (See Mark 9:25.)

Verse 15. - This verse in the Vulgate is contained in ver. 14. Have mercy on my son. According to St. Luke, the father makes his plea more touching by adding that he was his only son - an appeal to which the Saviour's tender heart was always open, as when he stopped the bier at Nain, and said to the childless widow, "Weep not." He is lunatic (σεληνιάξεται). The Revised Version most unnecessarily renders the verb, he is epileptic. Doubtless the case in many respects simulated epilepsy, and might have been so described; but it seems inexpedient to conceal the actual word used, which gave the popular and probably correct view of one phase of the complaint. Surely a real fact well known to medical science underlies the term lunacy, in the catalogue of the diseased persons who were brought to Christ to be healed (Matthew 4:24), we find a class called lunatics, distinct from the paralytic and possessed. It is by no means an exploded fallacy that the moon has some mysterious influence on certain constitutions, and produces an aggravation of symptoms in accordance with some of its changes. It was from observation of this phenomenon that this form of insanity was termed seleniasmus or lunacy. In the present instance the disease was complicated and of no ordinary nature. The other synoptists state that the child was possessed by a demon. This was the fact which differentiated the malady from any merely organic sickness. It was in truth epilepsy accompanied by or occasioned by demoniacal possession. St. Matthew does not mention the possession in his introductory account, but he afterwards (ver. 18) speaks of the demon departing. Sore vexed (κακῶς πάσχει); is in evil case; suffers grievously. He was affected with terrible paroxysms, which are detailed more at length by Mark and Luke. Matthew narrates some of the effects of the mania upon the victim. Ofttimes he falleth into the fire. The fits, coming on suddenly and without warning, brought the sufferer into imminent dangers, perhaps produced suicidal tendencies, which urged him to destroy himself.

17:14-21 The case of afflicted children should be presented to God by faithful and fervent prayer. Christ cured the child. Though the people were perverse, and Christ was provoked, yet care was taken of the child. When all other helps and succours fail, we are welcome to Christ, may trust in him, and in his power and goodness. See here an emblem of Christ's undertaking as our Redeemer. It encourages parents to bring children to Christ, whose souls are under Satan's power; he is able to heal them, and as willing as he is able. Not only bring them to Christ by prayer, but bring them to the word of Christ; to means by which Satan's strong-holds in the soul are beaten down. It is good for us to distrust ourselves and our own strength; but it is displeasing to Christ when we distrust any power derived from him, or granted by him. There was also something in the malady which rendered the cure difficult. The extraordinary power of Satan must not discourage our faith, but quicken us to more earnestness in praying to God for the increase of it. Do we wonder to see Satan's bodily possession of this young man from a child, when we see his spiritual possession of every son of Adam from the fall!Lord, have mercy on my son,.... He addressed him with great marks of honour and respect, not only by gesture, but by words; he craves mercy, pity, and compassion; for the case he had to present, was a miserable one; and his earnestness and importunity he hoped might be excused, since it was for a child of his own. Luke adds "for he is mine only child"; and therefore his affection for him must be thought to be very strong, and he greatly concerned for its grievous affliction, and earnestly desirous of its health and life.

For he is lunatic: not a mad man, but troubled with the epileptic disease; upon which, as on madness or lunacy, the changes and full of the moon have an influence: hence the next clause,

and sore vexed, is rendered in the Arabic version, "and sore vexed at the beginning of full moons"; at which times, he had very grievous and frequent fits of his disorder:

for ofttimes he falleth into the fire, and oft into the water: which shows it to be the "epilepsy", or "falling sickness", he was afflicted with; which, whenever it seized him, whether by the fireside, or by the side of a river or brook, or any place of water, or in any other dangerous situation, he fell into it, not being able to help himself, or avoid any danger to which he was exposed. A larger account of this child's disorder, and of the circumstances of his cure, are related by Mark 9:17 where this case will be more fully considered. See Gill on Mark 9:17. See Gill on Mark 9:18.