What does Romans 2:21 mean?
Paul has set his Jewish readers up for a series of difficult questions. His larger purpose is to challenge those who assume that being Jewish means they do not have to worry about God judging them for their sinfulness. They believe the law of Moses stands between them and God. In a broader sense, this point is meant to apply to anyone who tries to rely on their own religiosity in order to be right with the Lord.Paul has asked a series of leading "if" questions: If you are a devout Jew, if you rely on the law, if you boast in God, if you are sure you are a guide to the blind, if you're a teacher of the foolish and of children, if you truly have the law which you believe to be the embodiment of knowledge and truth…then why don't you follow it?
More specifically, Paul begins in this verse by asking why the teachers don't teach themselves. He then follows with three examples of not following the law. If they preach against stealing, do they steal? It's not clear what, if any, examples of theft Paul has in mind. What is clear is Paul's larger point: Having the law is not enough. You must also keep it. And, as he will explain later in this letter, nobody can perfectly keep it (Romans 3:10).