There are many Christians suffering from a range of physical ailments and conditions. Some also suffer mentally from their conditions, whereas others have been able to look beyond their situation to find peace.
It is important to understand one thing that is quite contrary to what some churches preach today.
The Gospel of Jesus Christ and the teachings of the New Covenant are not about the flesh, but are teachings about the spirit of man.
Old Covenant focus
The Old Covenant was focused on the flesh and the purpose of the law was to define right and wrong in the hope that man would choose not to sin. It is because of sin into which every person is born, that people get sick and die. We die because we have sinned and are born into sin, and death is the penalty for sin.
In the flesh, there is no way to escape death. But in the Spirit, God has provided the way of escape from death through Jesus Christ.
New Covenant focus
The New Covenant is targeted at the spirit of man, not the flesh. It doesn't really matter what happens in our flesh. If we get sick, if we are ill, if we suffer debilitating diseases, or are maimed and afflicted in the flesh, it doesn't really matter.
The flesh is doomed to die. If we have to put up with illnesses for the few short years of this life, it is nothing compared to eternity with Christ. This physical body we inhabit is designed to grow old and die.
But the spirit that God has given to each of us, that part of us that is "who we are," is not destined to grow old or die, provided that we seek the eternal life that is in Jesus Christ.
When we understand this, we have no cause to worry because we know that this body is destined to wear out and die.
In spite of these things, the mind remains young and active. In my case, in my spirit I feel no different than I did when I was a young man because the spirit of a person does not age.
The body dies but the spirit is alive
Let's consider a few scriptures.
If Christ is in you, although your bodies are dead because of sin, your spirits are alive because of righteousness. (Romans chapter 8, verse 10)
Our bodies are dead and doomed to die because we were all sinners. We cannot escape this judgement that falls upon all mankind, Christians or not. But in Christ we are alive in the spirit because we receive the free gift of righteousness from God. If we choose to follow Christ, our spirits will live on into God's kingdom, even though our bodies will deteriorate and die.
The flesh is of no avail
It is the spirit that gives life, the flesh is of no avail; the words that I have spoken to you are spirit and life. (John chapter 6, verse 63)
Jesus said that the flesh is of no avail. It is unimportant because it will die. But the spirit gives life and the spirit lives on.
We need to sow seeds to the spirit through faith and learning the ways of God, rather than worrying about the issues of the flesh. As Romans 8 says, "Set your mind on the things of the spirit," and as Jesus said above, His words are not about the flesh, but are "spirit and life."
Pure spiritual food
There are many other scriptures saying similar things, but I hope this is enough to show that the ministry of Jesus is not about the flesh but about the spirit.
As such we need to be fed with the pure spiritual food that comes from God through the Gospel of Jesus Christ and the teachings of the New Covenant.
Sadly, some sections of the modern church are not focused on the spirit, but are teaching things of the flesh. The doctrines of divine health, prosperity gospel, and the like are all focused on the flesh of man, not the spirit. They look at the flesh as though that is what is important, and it isn't.
God’s promises
Yes, the Lord has given us the ability to find healing through prayer and anointing with oil. But nowhere did God promise we would not get sick, as the proponents of the divine health doctrine propose.
Likewise, Jesus promised us great wealth in the spiritual things, but nowhere in the Bible does He promise financial prosperity as the proponents of the prosperity gospel claim. In fact, if anything, Jesus advised against seeking physical wealth as it can lead you astray.
But what God DID promise is a wealth of the things that really matter: peace, love, protection in the spirit, joy, righteousness, holiness, and so on. What God DID promise as the outcome of our faith is eternal life, and He also promised us a new body that would not become feeble, grow old, get sick, and die.
So, focus your heart, mind, soul, and all of your energy on seeking the things of the Spirit rather than the things of the flesh. The flesh is of this world and is doomed to pass away. But the spirit is eternal and finding the things of the Spirit will lead to life.