ConclusionIt is not only possible to determine the nature of Paul's
"thorn in the flesh," but it is incumbent upon us to compare scripture with scripture in order to do just that! Paul parallels the "thorn" with an infirmity or "weakness" in which he will glory for Christ's sake, and in 2nd Corinthians 10-13 he links his weakness with persecution. Paul says that this thorn is a Messenger from Satan, which is never identified with sickness or illness in scriptures. The word messenger always refers to a human being or angel or Christ. By contrast, Thorns are seen continually in scripture, a signification of those who are of Satan.
2nd Corinthians 11:29-33
"Who is weak, and I am not weak? who is offended, and I burn not?
If I must needs glory, I will glory of the things which concern mine infirmities.
The God and Father of our Lord Jesus Christ, which is blessed for evermore, knoweth that I lie not.
In Damascus the governor under Aretas the king kept the city of the Damascenes with a garrison, desirous to apprehend me:
And through a window in a basket was I let down by the wall, and escaped his hands."
These men persecuted and troubled Paul, and in this pleading with God for deliverance, Paul would learn patience and where his help is. In this would Paul glory, not in that He was used marvelously of God and received great revelations.
2nd Corinthians 12:10
"Therefore I take pleasure in infirmities, in reproaches, in necessities, in persecutions, in distresses for Christ's sake: for when I am weak, then am I strong."
Paul desired and prayed that this Messenger of Satan be removed from Him three times.
The Number Three is the number of God's Purpose and will. It was not God's will that Paul have no persecution nor trouble from the Messenger of Satan. God tells us, We all shall have it. Indeed, through this trouble, Paul would be brought to a closer dependence upon Him, wherein his strength is made perfect in weakness. God's answer to Paul's prayer was that His Grace was sufficient for him. The Salvation of God was enough! The Lord didn't remove this Messenger of Satan, He instead gave him the strength to endure it. And in this, Paul could glory, and rejoice in the Power of Christ.
2nd Corinthians 13:3-4
"Since ye seek a proof of Christ speaking in me, which to you-ward is not weak, but is mighty in you.
For though he was crucified through weakness, yet he liveth by the power of God. For we also are weak in him, but we shall live with him by the power of God toward you."
Such is the end of the matter. Paul rejoiced in his weakness, that the power of Christ rested upon him. Paul came to understand Grace was all that is necessary. It wasn't necessary that Paul's work go un-fettered, or that He be allowed to preach un-persecuted by the Messengers of Satan, for it's not by works, but by Grace we are Saved. And these persecutions and troubles only made him strong in the Lord. They worked patience. We are not justified by anything we do, but by Grace. And it was sufficient!
Titus 3:5-7
"Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;
Which he shed on us abundantly through Jesus Christ our Saviour;
That being justified by his grace, we should be made heirs according to the hope of eternal life."
So why do so many theologians misinterpret Paul's thorn to mean sickness? In some instances, the reason is as simple as the word "motive." Some who are against the cessation of signs and healings do it in an attempt to prove that the Devil can place sicknesses in believers, and therefore they are given the gift of healing to combat it. Still others who are for the cessation of Signs and Healings do it in an attempt to prove that Paul couldn't heal himself, therefore they reason this gift of healing was not meant for the Church after the canon was completed. Ironically enough, in their zeal to prove the cessation of the signs gifts, many of the cessationist camp "choose" to do something they don't normally do, which is to ignore the
"Sola Scriptura" principle and pay no heed to the pertinent scriptures, in order to claim that this thorn was an illness. But the end doesn't justify the means, and their agenda clouds their judgment. While on the other hand, many of the anti-cessationist camp rightly search the scriptures and present scriptures that prove that this thorn in the flesh messenger of Satan was not illness. In this, they have it right, even though in the big picture, they have it all wrong.
God made it clear that Jesus bore our sickness and infirmities, and that He did it by the cross. It was our "sin sickness" that He went to the cross to heal, not our physical sicknesses. The Signs and wonders which He did in healing physically, were "types" pointing to the power of His blood. But the Thorn in the flesh, which was the Messenger of Satan, was not physical illness. It was the persecutors of God's servants. It's normative for the believer, and they had to endure it. Grace was enough for them.
God instructs us that in this world we "shall" have tribulation. That's the nature of true Christianity. It always has been. People hate you, resent you and all that you testify of. When you come with the truth of the gospel, that enmity is a given. They therefore revile and persecute you because of it. These are the thorns in the flesh, the Messenger of Satan. The reproaches, the necessities of life, the persecutions and the infirmities, yes Paul had them. We all do.
Every Christian has some illness at sometime in their life. But Satan didn't give it them to them. Illness isn't a messengers of Satan that is placed in our body and sent to buffet us. That is a myth borne of unsound and unbiblical suppositions. Satan works from without the body, through other evil men, not from within our Body.
On the other hand, when the scriptures themselves say that this Thorn in the flesh was "A
Messenger of Satan" I'd say we're on safe ground saying (testifying) that it was a messenger of Satan. Who would disagree? We know that no messenger of Satan is put within a Christian's body, it is impossible for Him to dwell there with Christ. And considering the myriad of scriptures (which I've only barely touched on) that illustrate that the thorns in believers are those Messengers of Satan are men who are false Prophets, fallen Congregationalists, evil men, etc., I'd say we're on solid ground. In other words, we have shown where a thorn in the flesh is used by God to symbolize those of Satan who come against, and buffet believers. God calls them "thorns in their sides." Can anyone show us one scripture that says a thorn in the flesh (or side, hand, toe, anywhere) is a disease, ailment, or sickness? What I'm saying is, interpretations must have some Biblical foundation. It's the most basic rule of biblical hermeneutics. If we start out with pre-suppositions like "it's a physical ailment", we end up with mind block where we won't even consider other possibilities.
All the Disciples had ailments, and they all "died from ailments" if they were not martyred. As you and I will probably die from an ailment (if Christ doesn't return before, or we're in an accident or killed). Ailments are a normal part of life, not a messenger from Satan. The miracles the disciples did of healings were "signs" for the completion of the scriptures. When the Holy canon was completed, the Signs pointing to salvation and Christ ceased. The only prophesies of end time or future signs and wonders now are references to Satanic activity (rev. 13, 2nd Thess. 2, matt. 24, etc.). Can I convince anyone of this? No, not in a hundred years of writings. But God can. Truth is discerned not by my feeble writings, but by the Holy Spirit working within each believer, through the searching and careful consideration of God's divine word.
..May the Lord who is Gracious above all, give us the Wisdom and understanding to discern His truth.
Amen!
Again taken from the studies of Tony Warren. Just another mans opinion but a good one! 
Paul