Ver. 7-10. A sting of my flesh,[1] an angel, or a messenger of Satan, to buffet me. The Latin word signifies any thing that pricks or stings, the Greek word a sharp stick or pale: he speaks by a metaphor, as also when he says to buffet me; that is, by causing great trouble or pain. Some understand by it a violent headache or pain, or distemper in the body. St. Augustine mentions this opinion, and does not reject it, in Psalm xcviii. tom. 4. p. 1069.; in Psalm cxxx. p. 1465. St. Jerome also speaks of it in chap. iv. ad Galatas, tom. 4. p. 274, Ed. Ben. But St. Chrysostom, by the sting, and the angel of Satan, understands that opposition which St. Paul met with from his enemies, and those of the gospel; as Satan signifies an adversary. Others understand troublesome temptations of the flesh, immodest thoughts, and representations, suggested by the devil, and permitted by Almighty God for his greater good. — Thrice I besought the Lord. That is, many times, to be freed from it, but received only this answer from God, that his grace was sufficient to preserve me from consenting to sin. And that power and strength in virtue should increase, and be perfected in weakness, and by temptations, when they are resisted. St. Augustine seems to favour this exposition, in Psalm lviii. Conc. 2. p. 573. St. Jerome, in his letters to Eustochium, to Demetrias, and to Rusticus, the monk. And it is the opinion of St. Gregory, lib. 23. moral. tom. 1. p. 747. and of many others. (Witham) — If there were any danger of pride from his revelations, the base and filthy suggestions of the enemy of souls must cause humiliations, and make him blush. But these are to be borne with submission to the will of God, for his power is more evident in supporting man under the greatest trials, than in freeing him from the attacks. — Power is made perfect. The strength and power of God more perfectly shines forth in our weakness and infirmity; as the more weak we are of ourselves, the more illustrious is his grace in supporting us, and giving us the victory under all trials and conflicts. (Challoner) — When I am weak. The more I suffer for Christ, the more I perceive the effects of his all-powerful grace, which sustains, enlightens, and strengthens me: the more also the glory and power of God appeareth in me. The pagans themselves were not ignorant that calamity was the soil in which virtue usually grows to perfection. Calamitas virtutis occasio est. (Seneca) — Optimos nos esse dum infirmi sumus. (Pliny vii. ep. 26.)
That was my first thought, too!