Alarmed at the influence of false teachers in the Corinthian church (whom Paul called “false apostles, deceitful workmen, and servants of Satan”), Paul addressed the problem head-on.  The false apostles had been boasting about themselves, slandering Paul, and being abusive to the Corinthian believers.  Paul, against his better wishes, decided to speak in the same language as the false apostles, in order to get the Corinthians’ attention:  namely, the language of foolish boasting.  Paul believed the real credentials of a servant of Christ are measured by the hardships endured while serving Jesus.  He then laid out (in boastful fashion) a long list of the many serious, dangerous hardships he has endured as a servant of Jesus, re-confirmed his love for the Corinthians, and ended up boasting about his weakness. 
2 Corinthians  11:16-33