The third of the Epistles is Paul's second letter to the Christians in Corinth, or II Corinthians. Some members of the Church in Corinth had challenged Paul's authority over them and so he had sent two of his followers, Titus and Timothy, ahead before setting off himself to Corinth. Titus returned from Corinth and reported to Paul that the Christians there had repented of their challenge to Paul's teaching. This heartened Paul, but there were still some issues which need dealing with, and so he wrote this second letter.
II Corinthians 12:7-10
"And lest I should be exalted above measure through the abundance of the revelations, there was given to me a thorn in the flesh, the messenger of Satan to buffet me, lest I should be exalted above measure. For this thing I besought the Lord thrice, that it might depart from me. And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities, that the power of Christ may rest upon me. 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"