Philippians 3:1-3

Finally, my brothers, rejoice in the Lord! It is no trouble for me to write the same things to you again, and it is a safeguard for you.

(v1, NIV)

Paul is simply repeating what he has been saying throughout this letter. The theme is joy and he is reminding them to rejoice. He even points out that it's not a big deal for him to repeat these things. In addition, a reminder to rejoice is beneficial for his readers.

Watch out for those dogs, those men who do evil, those mutilators of the flesh.

(v2, NIV)

Paul is talking about those who oppose the gospel. These were possibly Jews who were legalists. The three descriptions he gives are not desirable in any sense. Specifically, they may have been false teachers. These people may have been distorter of the gospel or promoters of some sort of salvation by good works. These are clearly wrong and that is why Paul calls them the way he does.

For it is we who are the circumcision, we who worship by the Spirit of God, who glory in Christ Jesus, and who put no confidence in the flesh—

(v3, NIV)

When Paul refers to "we" he is talking about himself and the believers at the church in Philippi. We are followers of the living God. The ESV says "real circumcision" instead of just "circumcision". Compared to others, we are real and they are fake. The Jews may have been boasting about their circumcision, but we who follow the Lord Jesus Christ are the ones who are truly circumcised. Most importantly, we put no confidence in the flesh. They may have been boasting about fleshly things like circumcision, but we do not do that. There is nothing good to boast about in our flesh. We boast in the Lord.

What types of things may we put confidence in? Well the Jews boasted in their circumcision. They boasted that they were descendants of Abraham. Are you boasting about some mark you received on your body? Are you boasting about your history or your upbringing? We are not saved because of who our mother is. Our parents may be the ones who tell us about Jesus, but it is only by grace through faith in Jesus that we are saved. Maybe we may put confidence in our abilities, like our intelligence or looks or physical fitness. These things will all pass away. There will always be someone smarter than you or someone better looking than you or someone stronger than you. Even if you are the wisest or the strongest person on earth, what is that compared to God? It is nothing compared to God. Do not put confidence in the flesh.