Where is boasting then? It is excluded. But what law? Of works? No, but by the law of faith.
Because Christ died to atone for sins, lost sinners are justified through believing on Him. That is God’s objective in His righteousness and grace.
But then Paul once again mentions boasting (cf. also ch.2:v.17). He knew the danger of having a good opinion of oneself and imagining that God must acknowledge our merits and good deeds: “If anyone else thinks he may have confidence in the flesh, I more so: circumcised the eighth day, of the stock of Israel, of the tribe of Benjamin, a Hebrew of the Hebrews; concerning the law, a Pharisee; concerning zeal, persecuting the church; concerning the righteousness which is in the law, blameless. But what things were gain to me, these I counted loss for Christ” (Philippians 3:4-7).
Paul had renounced any boasting for Christ’s sake. He was aware how great his guilt was: in his religious zeal he had persecuted the early Christians!
But this danger does not affect only Pharisees of the Jews. Boasting is excluded not just for them. In the epistle to the Ephesians we read that both heathen and Jews are considered “dead in trespasses and sins”. It then continues: “For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest any man should boast” (ch.2:vv.1.8.9). Any boasting is thus out of place and excluded. The law or principle of works leads only to man’s condemnation; the principle of faith, however, by which people must be saved, will not admit of boasting.
Image: By Gustave Doré – http://www.gutenberg.org/files/8710/8710-h/p7.htm#077, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3523289