Prayer against evil spirits in others may have to be accompanied by the inaudible commanding of them to leave the person, or else in casting out the demon, or demons, directly and audibly. There are several conditions for doing this, which need careful and prayerful consideration, ere such a course is taken. The possessed person may first need (1) truth upon his condition, and the ground wherein the evil spirit has found lodgment. This requires knowledge and discernment on the part of the worker, and sometimes very exhaustive dealing with the possessed one; (2) the ground which has been discovered must be given up definitely and specifically by the victim,note 22 or the "casting out" may fail; (3) definite prayer to God for His will to be revealed concerning the whole matter, and how the Spirit of God would have it dealt with, is primarily necessary; (4.) the authority of Christ needs to be specifically taken by the one called upon to deal with the man, and (5) wrestling prayer which reaches "fasting" may be needed if the case is a very difficult one.note 23
The fasting which is of spiritual effect in such a case, means, that the one who is dealing with the possessed person, is brought into such a hand to hand conflict of spirit with the evil spirit, or spirits, in possession, that the sense of any bodily need ceases until the victory is won.
The Lord's wilderness conflict throws light upon this, for it appears that it was not until after Satan had left Him, and the tension of the conflict was over, that His physical needs asserted themselves, and "He hungered" (Matt. 4: 2). True "fasting," therefore, appears to be not so much the result of a believer's choice and determination to fast from food, as the result of some spirit-burden, or conflict, which constrains him to fast because of the dominance of the spirit over his body, and no sense of physical need at all. But when the conflict is over and the spirit disengaged, the requirements of the body make themselves felt once more.
There is also a permanent attitude toward the body, which may be described under the word "fasting," which is a necessary condition for continuous victory over evil spirits. Especially for the casting out of evil spirits, it is imperative that the believer has complete mastery over his body, able to discriminate between its legitimate demands, and the spirits of evil seeking to gain a footing behind its lawful needs, and to detect all the wiles seeking to rob him of victory over them.