Apostle Paul's Logic in 2 Corinthians 12

"Therefore, in order to keep me from becoming conceited, I was given a thorn in my flesh, a messenger of Satan, to torment me. Three times I pleaded with the Lord to take it away from me. 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. 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."
- 2 Corinthians 12:7-10


What D. Martyn Lloyd-Jones thinks the apostle's logic was in that passage:

1. Conditions are always changing, therefore I must obviously not be dependent upon conditions.
2. What matters supremely and vitally is my soul and my relationship to God--that is the first thing.
3. God is concerned about me as my Father, and nothing happens to me apart from God. Even the very hairs of my head are all numbered. I must never forget that.
4. God's will and God's ways are a great mystery, but I know that whatever He wills or permits is of necessity for my good.
5. Every situation in life is the unfolding of some manifestation of God's love and goodness. Therefore my business is to look for this peculiar manifestation of God's goodness and kindness and to be prepared for surprises and blessings because 'His ways are not my ways, neither His thoughts my thoughts'. What, for example, is the great lesson that Paul learned in the matter of the thorn in the flesh? It is that; 'When I am weak then am I strong'. Paul was taught through physical weakness this manifestation of God's grace.
6. I must regard circumstances and conditions, not in and of themselves therefore, but as a part of God's dealings with me in the work of perfecting my soul and bringing me to final perfection.
7. Whatever my conditions may be at this present moment they are only temporary, they are only passing, and they can never rob me of the joy and the glory that ultimately await me with Christ.

from Spiritual Depression by D. Martyn Lloyd-Jones
(I highly recommend it for any believers!)