Coming now to verse 17, we have a key to the interpretation of the passage.  At the beginning of chapter 2, Paul speaks only to a hypothetical individual he calls “O man,” not identifying whom he is addressing.  But now that little mystery, if such there was, is cleared up, for he plainly says, “Behold, thou art called a Jew…”  This argument, then, is directed against the Jew, who would have agreed with the apostle’s dim assessment of the heathen Gentiles, while fancying himself to be in much better shape because of his noble heritage and diligent observation of the law of God.

Paul is pleased to give his brethren their due, but also intends to blast away all the ramparts of their self-righteousness with a shot from the Gospel cannon.  He begins by describing the Jew, and his claims.  He is called a Jew, which involves the mighty privilege of coming from the family chosen and blessed by God, possessing the oracles of God, and counting many mighty men of faith among their kin.  But when Paul says that he rests in the law, it is no compliment, though the Jew may ignorantly have taken it so.  As we will find by proceeding throughout this epistle, nothing is more destructive to the soul than to lean our confidence upon our own doings.  To rest in the law is to vainly imagine that the executioner waiting to behead us will somehow become the friend that delivers us from every peril. 

The Jew made his boast in God, which undoubtedly means he prided himself on the knowledge he had of God from the reading of the scriptures and the teachings of the Rabbis.  Doubtless these were tremendous advantages, but they should have been a matter of humble thankfulness rather than boasting.  The Jew knew the will of God, being familiar with His law.  He knew what God expects from men, the things He approved, and those things He forbids.  Once more, these things are all very well to know, but such knowledge should lead to humble thankfulness to the great God Who revealed these things to us.  Because he knew the law of God, and what it required of men, and paid some degree of homage to it, the Jew could justly be said to approve the things that are more excellent.  Truly, the Jew had a knowledge more excellent and more helpful than all of the wisdom of Plato, Socrates, and Aristotle combined.  He delighted in the knowledge he had of God’s law, and immersed himself in the study of it.  As he embraced this excellent knowledge, he came to a proud confidence that he himself could be a guide to the blind, bringing proselytes out of heathen darkness and shining the light of God’s law into their minds.  Thus, he became a guide of the blind, a light to them who sat in darkness.  He became an instructor of babes, teaching even the wise men of the heathen world a better knowledge than their mightiest philosophers had ever developed.  In short, Paul says that the Jew had “the form of knowledge and of the truth in the law.”  These, unquestionably, were mighty privileges, and Paul by no means wishes to demean them.  However, he is going to prove beyond the shadow of a doubt that, great as these privileges were, none of these things by themselves gave the Jew an advantage over the heathen Gentiles to whom they considered themselves guides and lights.