We have this treasure in jars of clay. The church at Corinth was infested with so-called super-apostles. They were stylish and well-spoken, and they were out to turn the church against the apostle Paul. They cast him as a frail, indecisive fumbler who got beat up everywhere he went. So Paul responded with a full-length Canon Press resource: https://canonpress.com/products/diamonds-in-a-cardboard-box-a-commentary-on-the-second-epistle-to-the-corinthians