Paul boasts in Jesus, not Self.
6:14Holman Christian Standard Bible (HCSB)
14 But as for me, I will never boast about anything except the cross of our Lord Jesus Christ. The world has been crucified to me through the cross, and I to the world.
You want to come here to teach the scriptures but you do not even know them.
Paul says he wants us to boast in each other.
For we do not write you anything you cannot read or understand. And I hope that, as you have understood us in part, you will come to understand fully that you can boast of us just as we will boast of you in the day of the Lord Jesus. See 2 Corinthians 1:13,14.
Paul shows us we can boast in ourselves.
2 Corinthians 1:12 Now this is our boast: Our conscience testifies that we have conducted ourselves in the world, and especially in our relations with you, with integrity and godly sincerity. We have done so, relying not on worldly wisdom but on God's grace.
2 Corinthians 7:14 I had boasted to him about you, and you have not embarrassed me. But just as everything we said to you was true, so our boasting about you to Titus has proved to be true as well.
1 Thessalonians 2:10
You are witnesses, and so is God, of how holy, righteous and blameless we were among you who believed.
2 Corinthians 12:6
Even if I should choose to boast, I would not be a fool, because I would be speaking the truth.
Acts 23:1
Paul looked straight at the Sanhedrin and said, "My brothers, I have fulfilled my duty to God in all good conscience to this day."
Paul boasted in himself.
1 Corinthians 9:15 But I have not used any of these rights. And I am not writing this in the hope that you will do such things for me, for I would rather die than allow anyone to deprive me of this boast.