john11:4 When he heard this, Jesus said, “This sickness will not end in death. No, it is for God’s glory so that God’s Son may be glorified through it.” NIV
Some believers hold the view that God usually put sickness on his children so that he can take glory. That's far from the truth of the scriptures. Saying that God would intentionally put sickness on his children makes him look wicked. God doesn't create problems because He want to shine through it. It is against the nature of God from scriptures. The devil is the author and finisher of sickness. In Luke 13:16, Jesus spoke about the woman that was bent double as being tormented by the devil. In fact, she was bound by the devil not God.
In Matthew 8:17, the gospel of Matthew made it clear that Jesus took our infirmities. If he took our infirmities, we should seek to know who is putting it on God's people. Of course, it is the devil. In Acts10:38, the writer made it clear that sickness is an oppression of the devil. How can God borrow the tool of sickness from the devil so that he can take glory? Just think about it. The last time I checked the gift of the Spirit, the gift of healing was boldly written not the gift of sickness. Some preachers sometimes say things that can't be proven from scriptures and they make a doctrine out of them. Healing was a principal ministry of Christ while on earth, and I'm glad to tell you that Jesus is still in the business of healing today because he is the same yesterday, today and forever. Heb13:8.
If there's a sickness in your body, I'm glad to tell you that the price for your healing has been paid on the cross. God's desire is to take glory from healing you not from your sickness. Glory comes to God when the lost is saved and restored, when the sick is healed and when the oppressed is delivered. You have a choice to make, either to stay in sickness or to receive healing. It is as simple as receiving the gift of salvation. To receive your healing, you need to believe Christ has done it just as you believed your sins were forgiven when you came to Christ.
Father, I cast out the demon of sickness, (...mention name) in the name of Jesus.