All speculations as to what was the nature of Paul's thorn in the flesh end in nothing. God has wisely seen fit to leave it untold. Were it made known, we would have perhaps settled that it was not ours, and then have left it there. To have left it untold gives us to see that there was a great principle of God's dealings seen in this man's case, but applicable to all. Each would have his suited "thorn," the very thing that would counteract his natural tendency, and so act as to strip him of every pretension to power, and break any fancied strength of man.
We see this on every hand; we see it better in our own soul's history. For it is not always permitted for another to know the secret thorn which rankles in the breast, and which we would like to remove, ere we know the "end of the Lord." He presses home the "stake" which pins us to the earth, as it were, in powerlessness. You see this at times, for instance, in incongruous marriages. The soul is worn away, especially in a sensitive, spiritual mind; and there is no earthly power which can change the sorrow, and heavenly deliverance is withheld. Again, there is a child whose conduct breaks the heart of a parent; every measure fails in dealing with him and the "thorn" rankles deeply in the wounded heart. It may be that some disgrace is permitted, and the soul feels that death would be easier to bear. It may be that slander has stung the soul with deeper pain. There may too be some human weakness which renders the afflicted one an object of pain to those who love him, or of ridicule to others. Such as these, and the many sorrows of the way, are used of God as the "thorn" to curb the energy, to break the strength of "man". Circumstances, friends, relations, health, good name, are all touched by Wisdom in this holy discipline of the soul. These things in the hand of God are like the river banks which on either side guide the stream of waters which flow between them, rendering the waters useful and fruitful; which, if flowing onward without these guides, would devastate all around instead of bringing a blessing with them. Have we not often thought what good Christians we might have been if circumstances were different? In short, if the banks which carry the river were broken down. No, these are the wise dealings of our God to keep us just in the channel and path where we are, to shine for and glorify Him.
Like Paul of old when the "stake" was driven home, we may cry to God even thrice, as he did: Take away this thorn, this terrible hindrance to the work of Christ, this feebleness of the vessel, this sapping of energy, this hindrance to service, this cruel "stake" from which the soul struggles in vain to be free. But no; there it remains until we find in the acceptance of its bitterness the occasion of strength which is not of man, but which empties us of fancied human power. We learn our powerlessness; we feel that struggling is but in vain. Yet here the secret of strength is found, but not of man, not our own. The Lord comes in. He finds the vessel bereft of strength, prepared for that power with which He can wield it. He finds that condition which is His to use. "And He said unto me, My grace is sufficient for thee; for My power is made perfect in weakness. Most gladly therefore will I rather boast in my weaknesses (it is not infirmities but weaknesses in which he glories), that the power of Christ may rest (tabernacle over) me." "The surpassingness of the power is of God, and not from us."
Those who publicly serve the Lord in the Word know in measure these things. They know well, much as they may be blessed and valued too, what bitter lessons they have to learn in secret with the Lord. They could never be explained to another; yet they are only the emptying of fancied strength in man. Every true servant will find this out for himself; he will recall those moments when death was working in the fragile vessel, that life might work in those to whom he ministered. Yes, he begins to find how good these lessons are that made room for the working of a power which he is conscious is not of himself, not of man; and that when he felt the abject weakness of his own heart, his Lord might step in and give him the victory.
Thus the vessel is brought by the hand of the Potter, often through bruisings and breakings and crushings on the wheel, to its true and blessed form in which God Himself can work alone, when the vessel would say, "Not that we are sufficient of ourselves to think anything as of ourselves, but our sufficiency is of God." And again, "We have this treasure in earthen vessels that the excellency of the power may be of God and not of us." This is forcible and striking. He does not allow that the power would be from God, as something apart from Him and conferred or imparted to us. No, but it is divine and yet inseparable from Him who works; it is from God, and yet not of us, as not only denying the thought that it might be so; but the word he uses still more emphasizes this, that the power is of God and not from us.
There is a threefold cord which must be found in the saint if he would serve his Lord aright: the motive, the energy, and the end. At times the motive may be right, and the end also, but the energy may be but the human vessel working out (as it supposes) the things of the Lord. All three must go together, and this is the object of this disciplinary process, that all may be of God, and not of man.