Paul begins by acknowledging the privileges of his own Jewish people. Because of their knowledge of God’s will, Israelites possess good powers of discernment (Romans 2:18): [You who] know his will and approve what is excellent, because you are instructed from the law.
This is not meant in an ironic sense. It is true that Israel has the advantage of a special instruction, and therefore has the edge over all nations. Solomon’s wisdom is unparalleled in Egypt and Greece. And there was a reason why Daniel was the intimate advisor of a series of world rulers. God equipped Israel to be a guide to the nations (Romans 2:19–20a): [A]nd if you are sure that you yourself are a guide to the blind, a light to those who are in darkness, an instructor of the foolish, a teacher of children.
This is Israel, and they are well aware of it. Their status is due to the fact that in the Torah, the people have in the law the embodiment of knowledge and truth
(Romans 2:20b). For Paul the Jew, the Torah is the gateway to God. The truth that is being suppressed in the world of man (Romans 1:18) is now visible in the Torah of God. There the glory of the Almighty appears at Sinai and there the pillar of cloud of his splendor descends upon the temple. And while humanity is inclined not to acknowledge God, the knowledge of God is clearly and manifestly evident in the Torah.1
18 and know his will and approve what is excellent, because you are instructed from the law;