You, therefore, who teach another, do you not teach yourself? You who preach that a man should not steal, do you steal? You who say, Do not commit adultery, do you commit adultery? You who abhor idols, do you rob temples? You who make your boast in the law, do you dishonour God through breaking the law? For the name of God is blasphemed among the Gentiles because of you, as it is written.
In verses 17-20 Paul had acknowledged the Jews’ privileges. They had “the form of knowledge and truth in the law”. And how did they react? They based their merit and their right to teach the heathen on it.
The Jews clearly used the law as the standard for others. For themselves, however, it was an adornment that flattered them like a feather in their cap. This danger still exists today for all who pride themselves with Christian virtues. In fact, the Word of God is given to us primarily to instruct ourselves and then act accordingly.
These Jews practised the contrary to what they taught others from the law, whether it was in their interpersonal relations or with regard to God. True, they declined to serve idols, but they did not serve the true God, whom they professed to own, as He merited it, but rather “robbed” Him. They transgressed His law in numerous details. Through the actual conduct of many Jews then and many Christians today the heathen are given not a correct but a completely false picture of the true God. For that reason “the name of God is blasphemed” (cf. Isaiah 52:5).
Image: By El Greco – El Greco, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4751248