If we must boast, we will boast of the things that reveal our weakness. These are the things by which we are made weak in the eyes of our opponents. This is Paul's message to the people. He is bragging about his weakness because in here, it will show the sovereignty of our Lord in our lowest point.
We'll brag about the humiliations that make us like Jesus. This can also be a testimony to all of us. We experienced His great power in weakness. When we are weak, He is strong. That is how powerful the Name of Jesus is!