In 2 Corinthians 12 (NIV), the Apostle Pauls tells of some fantastic revelations that the Lord gave him. They were so amazing and Paul was evidently so vulnerable to becoming proud that the Lord had to protect him from this danger. Listen to what he writes:
7 “…because of these surpassingly great revelations…. in order to keep me from becoming conceited, I was given a thorn in my flesh, a messenger of Satan, to torment me. 8 Three times I pleaded with the Lord to take it away from me. 9 But he said to me, “My grace is sufficient for you, for my power is made perfect in weakness.”
“Therefore I will boast all the more gladly about my weaknesses, so that Christ’s power may rest on me. 10 That is why, for Christ’s sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong.”
It seems to me quite clear from this passage and in the Bible generally that the healing of the body is subservient to the needs of our spirit. That means that whenever having our bodies healed of some infirmity will best help us grow in our friendship with Jesus, healing will most assuredly be granted. But when healing the body stands to hinder our spiritual growth, God will give us grace in the middle of our affliction to keep growing and stay close to Jesus, not healing. The apostle Paul was the perfect illustration of this: God did not heal his physical infirmity which he called a “thorn in the flesh” because of the greater need in his spirit. And he tells us what it is he was being protected from. He writes, “to keep me from becoming conceited.”
And once he caught on to what the Lord was doing with his infirmity, and that it was actually occasioning a magnification of Christ’s power in his life, he switched up his attitude in a big way: “Therefore I will boast all the more gladly about my weaknesses, so that Christ’s power may rest on me. That is why, for Christ’s sake, I delight in weaknesses, in insults, in hardships, in persecutions, in difficulties. For when I am weak, then I am strong.”