Matthew 17:21, This kind. There are different kinds of demons that influence humans. The Testimony of Yeshua speaks of being “possessed with a demon” or “demons,” “vexed with a demon,” or “severely possessed with a demon” (Matt 4:24; 8:16, 28, 33; 9:32; 12:22; 15:22; Mark 1:32; 5:15, 16, 18; Luke 8:36; John 10:21).
All these ideas are expressed by the Greek word daimonizomai meaning “to be under the power of or possessed by a demon, or demonized.”
There are levels of demonization. The Bible reveals that demons can influence humans (e.g. from fiery darts of Satan shot at the saints by which he attempts to influence them [Eph 6:16], by lying to humans [1 Kgs 22:22–23], through unclean spirits [e.g. Matt 12:43; Mark 1:23, 26; 3:30] and by literally living in or possessing a person. The latter is the most extreme form of demonization.
In this passage, a demon lived inside of a child (v. 18), and when Yeshua rebuked the demon, it came out of the child. When a person is possessed with a demon, prayer and fasting may be necessary on the part of the deliverer to cast out the demon. This is because the deliverer has, to one degree or another, himself been weakened spiritually by faithlessness and perverseness and therefore lacks the spiritual power and faith to cast out the demon (vv. 17, 22), or because he has been negatively influenced by those around him who are this way (v. 17), and thus has been weakened by his spiritual environment. This is why Yeshua, at times, had to put the spiritually weak and faithless people out of the room before healing a sick person (Mark 5:40).
Prayer and fasting energizes a person spiritually by afflicting the soul (the mind, will and emotions) and forcing it into conformity with the word, will and Spirit of Elohim through which one gains the spiritual power to accomplish supernatural feats such as casting out demons.
