Twice, in the famous chapter of Romans 7, where Paul presents a first-person angst about our battle against sin, he says, "But this is not my true nature. This is not my heart."
As it is, it is no longer I myself who do it, but sin living in me. I know that nothing good lives in me, that is, in my sinful nature ... Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it ... For in my inner being I delight in God's law." (vv. 17-18, 20, emphasis added)
Paul is making a crucial distinction. This is not me; this is not my true heart. Listen to how he talks about himself in other places. He opens every letter by introducing himself as "Paul, an apostle." Not as a sinner, but as an apostle, writing to "the saints." Dump the religiosity; think about this mythically. Paul, appointed as a Great One in the kingdom, writing to other Great Allies of the kingdom. How bold of him. There is no false humility, no groveling. He says,
Surely you have heard about the ... grace that was given to me for you, that is, the mystery made known to me by revelation, as I have already written briefly. In reading this, then, you will be able to understand my insight into the mystery of Christ, which was not made known to men in other generations as it has now been revealed [to me]. (Eph. 3:2-5)
Paul is unashamed to say that he knows things no man before him knew. He even assumes they've heard about him, the mysteries revealed to him. That is part of his glory. His humility comes through clearly, in that he quickly admits that it's all been a gift, and in fact, a gift given to him for others.