2 Corinthians 12:7-10
Douay-Rheims
7 And lest the greatness of the revelations should exalt me, there was given me a sting of my flesh, an angel of Satan, to buffet me.
8 For which thing thrice I besought the Lord, that it might depart from me.
9 And he said to me: My grace is sufficient for thee; for power is made perfect in infirmity. Gladly therefore will I glory in my infirmities, that the power of Christ may dwell in me.
10 For which cause I please myself in my infirmities, in reproaches, in necessities, in persecutions, in distresses, for Christ. For when I am weak, then am I powerful.
Some claim it was an opponent, but most Catholic commentators in the past, note that this was a physical disability, or illness, of some sort.
Now, having endured the second worst winter of asthma in my life, and still not free from this keeping me up almost all night, I can identify with the Great Apostle to the Gentiles. One can pray and ask to be delivered from a physical oppression, but God does not always answer these prayers.
The same has been true of many saints. Padre Pio and John Vianney were allowed by God to be oppressed by many outside enemies, even those in their own dioceses and, in Padre Pio's case, his own order. They also had trouble sleeping as the demons were allowed to keep them awake at night.
Too many Catholics believe that if one is suffering, it is not God's Will.
Think again.