These and similar passages prove irrefutably that the Jews' arrogance and boast of circumcision over against the uncircumcised Gentiles are null and void, and, unless accompanied by something else, deserves nothing but God's wrath. God says that they have an uncircumcised heart. But the Jews do not pay attention to such a foreskin of the heart; rather they think that God should behold their proud circumcision in the flesh and hear their arrogant boasts over against all Gentiles, who are unable to boast of such circumcision. These blind, miserable people do not see that God condemns their uncircumcised heart so clearly and explicitly in these verses, and thereby condemns their physical circumcision together with their boasting and their prayer. They go their way like fools, making the foreskins of their heart steadily thicker with such haughty boasts before God and their contempt for all other people. By virtue of such futile, arrogant circumcision in the flesh they presume to be God's only people, until the foreskin of their heart has become thicker than an iron mountain and they can no longer hear, see, or feel their own clear Scripture, which they read daily with blind eyes overgrown with a pelt thicker than the bark of an oak tree.
If God is to give ear to their prayers and praises and accept them, they must surely first purge their synagogues, mouths and hearts of such blasphemous, shameful, false, and deceitful boasting and arrogance. Otherwise they will only go from bad to worse and arouse God's anger ever more against themselves. For he who would pray before God dare not confront him with haughtiness and lying, he dare not praise only himself, condemn all others, claim to be God's only people, and execrate all the others, as they do. As David says in Psalm 5:4: "For thou are not a God who delights in wickedness; evil may not sojourn with thee. The boastful may not stand before thy eyes; thou hatest all evildoers. Thou destroyest those who speak lies; the Lord abhors bloodthirsty and deceitful men." But rather, as verse 7 tells us: "I through the abundance of thy steadfast love will enter thy house, I will worship toward thy holy temple in the fear of thee."