The other thing I respect so much about him is that he admitted up front that he was no angel; instead he mentioned how it was a constant challenge for him to act on what he knew was right. He could've said he was unworthy for the job but he went on anyway realizing that God didn't expect perfection from him just that he lived the purpose God gave him to share Christianity. He certainly powered through the pain and suffering in his life with no earthly reward to look forward to.
I've been guilty of waiting to be worthy before pressing on with something I felt led to do. Next thing I know, a year has passed and I didn't get anything done because I never felt ready. Paul didn't worry about what he couldn't do and did what he could with what he had. He was an amazing man!