We continue on with the Good News that is Christ Jesus. That we are reunited with God through Jesus. We've had the bad and now have had the Good News. Paul, filled with the Spirit, is reinforcing that it is through grace and faith, and not by works, we are saved!
Why? Because he is faced with Jews who are saying that 'works play apart'. But it doesn't! Rather we are to stop boasting and bragging about our own efforts. This is being; 'self-righteous' and the truth is we can not be righteous by our own efforts. Paul has already referenced boasting (2:17) in association with the Jews and that when we boast in ourselves, we are not giving credit to God as we should be.
What we should be doing is recognising that it is through faith, faith apart from works and that works is actually an outcome of being 'in Christ'. We can link to Ephesians 2:1-10. This is apart from the law and works and only through faith. As a result, Jew and Gentile are under one God - the same God. You and I are different, yet what is the same? Our God. We are one under God, Jew, Gentile, you and me.
Paul then tackles a question he must have heard a hundred times, what use then is the law? Has it passed away? He says 'no'. Rather we are to uphold the law. He's already expressed what the law gives us, and that is an insight into who we are and our need for a saviour. The law's use is to help us see and to bring conviction of the sin in our lives. This then leads to our testimony of the Gospel (our witness to the world). It is also the guidance for us to lead a Christian life as it is the standard of God's own holiness.
For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— not by works, so that no one can boast. (Ephesians 2:8-9)
Boasting is a simple and basic sin. We are weak and sinful humans and we have two options:
We can take credit when things go right, or
We can boast in God, passing Him all credit
When we do the first option it limits our life and our worship. It doesn't give praise and honour to God and we end up reducing God to being a small god in our minds and our lives. And, when the bad days come, we end up not trusting in the small God we've manufactured and rather only have confidence in ourselves, when in fact it is ourselves who are limited. We believe instead that if we work harder good things will happen because God will reward us. But when trouble hits we have nothing tangible to hold onto because we have reduced God and we have become rooted in shallow soil.
What are we to do instead?
Worship and witness for the Lord. Praise and promotion of the Lord:
Therefore, as it is written: “Let the one who boasts boast in the Lord.” (1 Corinthians 1:31)
In God we make our boast all day long, and we will praise your name forever. (Psalm 44:8)