Paul's Authority

I am currently reading An Introduction to the New Testament by Carson and Moo. This introduction is great and I could not recomend a book more highly. Their writing style is great. Here is a section from their chapter on Paul: Apostle and Theologian:

Paul's apostolic stance enables him to interpret the Old Testament Scriptures with sovereign freedom and to make demands on his people that he considered to be as binding as anything in Scripture.