John Gill's Exposition of the Whole Bible
Matthew 17:18
And Jesus rebuked the devil,.... The words may indeed be rendered, "and Jesus rebuked him, and the devil departed out of him"; so the Vulgate Latin, and the Oriental versions; but the sense our version gives is certainly right; for it was not the father of the child Christ rebuked for his unbelief; this he had done already; nor the lunatic himself, as some have thought, either for his unbelief, or because he was possessed by the devil, for some sins of his own; which is not likely, since he was so from a child, and perhaps not now in his right mind, and capable of any rebuke: besides, the Evangelists Mark, and Luke expressly say, that he "rebuked the foul", or "unclean spirit": for though it was a natural disease which attended this child, yet he was afflicted with it in a preternatural way, by the means of Satan; who, by divine permission; had a power of inflicting bodily diseases: and that this disease was effected by him, is clear from the manner of curing, by the dispossession of him; for when
he departed out of him; at the command of Christ, whose power he could not withstand, but was obliged, whether he would or not, to obey;
the child was cured from that very hour; directly, immediately, and continued well, and in good health. Hence the word rendered lunatic, in Matthew 17:15 is in several Oriental versions, translated in the sense of "demoniac", or one possessed with a devil. The Arabic version renders it, "he is with a demon": the Persic thus, "on whom a demon hath power"; and the Ethiopic after this manner, "an evil demon takes hold on him". And it is usual with the Jews, to ascribe diseases to evil spirits; and perhaps this uncommon dispensation in the times of Christ, may give rise to such a notion; particularly, they ascribe this very same disease of the "epileptic", or "falling sickness", to the same cause, which they call x "Kordicus", or "Cardiacus", the "Cardiac" passion, which one of their commentators y explains thus.
"It is a disease which proceeds from the repletion of the vessels of the brain, whereby the understanding is confounded; wherefore it is one of the sorts חולי הנופל, "of the falling sickness".''
Says another z of them,
"It is שם שידה, "the name of a demon", that rules over such, that drink much wine out of the vat.''
To which others agree, saying a, that one attended with this disorder, is one,
"whose understanding is confounded, מחמת שד, "by means of a demon", who rules over such, that drink new wine; and lo! the spirit's name is "Kardiacus".''
From whence it is clear, that with them, the disease and the demon go by the same name; and that the former is from the latter.
x Misn. Gittin, c. 7. sect. 1. y Maimon. in ib. z Gloss. in T. Bab. Gittin, fol. 67. 2. a Bartenora Yom Tob. in Misn. Gittin, c. 8. sect. 1.