“Heal the sick, cleanse the lepers, raise the dead, cast out devils: freely ye have received, freely give.”
King James Version (KJV)
10:8 Cast out devils - It is a great relief to the spirits of an infidel, sinking under a dread, that possibly the Gospel may be true, to find it observed by a learned brother, that the diseases therein ascribed to the operation of the devil have the very same symptoms with the natural diseases of lunacy, epilepsy, or convulsions; whence he readily and very willingly concludes, that the devil had no hand in them. But it were well to stop and consider a little. Suppose God should suffer an evil spirit to usurp the same power over a man's body, as the man himself has naturally; and suppose him actually to exercise that power; could we conclude the devil had no hand therein, because his body was bent in the very same manner wherein the man himself might have bent it naturally? And suppose God gives an evil spirit a greater power, to effect immediately the organ of the nerves in the brain, by irritating them to produce violent motions, or so relaxing them that they can produce little or no motion; still the symptoms will be those of over tense nerves, as in madness, epilepsies, convulsions; or of relaxed nerves, as in paralytic cases. But could we conclude thence that the devil had no hand in them? Will any man affirm that God cannot or will not, on any occasion whatever, give such a power to an evil spirit? Or that effects, the like of which may be produced by natural causes, cannot possibly be produced by preternatural? If this be possible, then he who affirms it was so, in any particular case, cannot be justly charged with falsehood, merely for affirming the reality of a possible thing. Yet in this manner are the evangelists treated by those unhappy men, who above all things dread the truth of the Gospel, because, if it is true, they are of all men the most miserable. Freely ye have received - All things; in particular the power of working miracles; freely give - Exert that power wherever you come. #Mark 6:7|; Luke 9:2.
Mt 10:8 Heal the sick, etc. Not only in order to do a beneficent work, but to demonstrate that they had the Lord's commission.