In these verses Paul is killing pride in ones own standing or achievements. He is saying that if salvation is by faith in Jesus alone then there is no defense in God’s judgement if we bring our own achievements as proof of righteousness.
Then verses 29-31 declares that God justifies all people in the exact same way. He says that if God required everyone to obey the law or be circumcised to be saved then the Jews would have an advantage but since he does not require those things then the ground at the foot of the cross is level for everyone.
Paul emphasizes that God saves by faith in Jesus Christ alone. So what does that mean for us?
Well, in chapter four Paul attacked the thought that family ties, religious connection, nationalism, goodness or anything else gives someone a leg up with God. So the question for you today is this:
What have you placed your faith in to save and secure your life here on earth and in eternity other than Jesus Christ?
Is your faith in your family, in your religious practices, in your national identity, in your goodness... or is your faith genuinely in Jesus Christ alone? How do you know? You know that your faith is in Christ alone if it is leading you to trust in Jesus and live in response the Gospel.
The text calls us to look at the life of Abraham. Chapter 4 says that righteousness was credited to Abraham because of his FAITH. We see from Abraham's example that faith was not mere belief. His trust filled belief or faith in God was not limited to his head and heart but was displayed through his life. Bottom line, Abraham choose to believe God would be faithful to provide a child who would become a great nation. And in order to see that promise fulfilled Abraham and his wife Sarah chose to be an active participants in creating that child. The "walked" in faith.
You know your faith is genuinely in Jesus if you are an active participant in a the way of Jesus.. in Kingdom living.
So... are you living and obeying in a way that allows God to live through you to accomplish is work? Or are you living to accomplish your own aims? The way you live is how you test where your faith lies.