When evening came, they brought to Him many who were demon-possessed; and He cast out the spirits with a word, and healed all who were ill. This was to fulfill what was spoken through Isaiah the prophet: “HE HIMSELF TOOK OUR INFIRMITIES AND CARRIED AWAY OUR DISEASES.”
Matthew 8:16–17 NASU
Matthew 8:16–17 quotes passages from Isaiah picturing the ministry of Messiah. Peter, in his first letter, revealed that “by whose stripes you were healed” (1 Peter 2:24b NKJV). In this Bible verse, we discern that healing and deliverance are related to one another. Please remember that a better translation for demon-possessed is demonized or under the attack of a demon(s). Another reference is found in Luke 9 where it records, “Then He called His twelve disciples together and gave them power and authority over all demons, and to cure diseases” (Luke 9:1 NKJV).
Lastly, we must consider the area of mental problems and demonic strongholds. Some mental illnesses have one or more demons causing the mental problems.
Mental problems can be based on physiological issues. These are medical concerns that have biological explanations. Of course, the healing grace of our God can come into play through the “gifts of healings” (1 Corinthians 12:9 NKJV). At the same time, mental problems can also be manifested in the attack of a demon(s). We saw this earlier in the Gadarene demoniac in Mark 5 and Luke 8:26–39.
Consider the young boy in Matthew 17:14–21 who apparently had what would today be diagnosed as epilepsy. This was a very strong demon that the disciples alone could not cast out. When Jesus rebuked the demon, and it came out of the boy, he was cured that very hour.
The disciples were wondering why they could not cast out the demon. Jesus explained to them: “Because of your unbelief; for assuredly, I say to you, if you have faith as a mustard seed, you will say to this mountain, ‘Move from here to there’, and it will move; and nothing will be impossible for you” (Matthew 17:20 NKJV).