No confidence in the flesh (v1-6)
Men by nature are arrogant and proud of what we accomplished in the flesh. Men also have the tendency to put our confidence, or to depend on our earthly experience, social status, power and money. Paul had many reasons to put his confidence in the flesh, but praise God he did not! Believers ought to put our confidence in Christ. We ought to worship by the Spirit of God, and glorify our Lord Jesus.
v2:[..what out for those dogs…do evil…mutilators of the flesh]. Paul was referring to Judaizers. It was common for Jews to refer to gentiles as dog, interestingly Paul referred the Judaizers as dogs because of their vicious and uncontrolled characters of insisting Christians to be circumcised.
Desire to know Christ (v7-11)
v7-11 is one of the most wonderful passages in NT that shows Christians what should be in the mind of a believer who desire to pursue Christ.
Nothing on this earth can be compared to the greatness of knowing our Lord Jesus Christ (v8). All things are considered rubbish when compared to the fullness and the glory of Christ (v9).
v11: [..to attain to the resurrection from the dead]. Paul did not mean he needed to obtain resurrection by works. He was referring to the subjective experience to die and to resurrect with Christ. Paul desired to share the suffering of Christ, to be united with Christ in death, and to experience the spiritual resurrection from dead.
Pressing on Toward the Goal (v12-14)
v13: [forgetting what is behind and straining toward what is ahead]. Paul is using the metaphor of runners in a race. Good runner does not look back to what he had accomplished but to press on toward the goal to win the prize.
Paul had accomplished much at this point in his life. But he was not satisfied and not wasting time to keep looking back. His desire is to press on to take hold of that for which God has prepared for him (v12,14).
All Christians are in a spiritual race. We have a common goal in life, which is to know, to experience, and to be like our Lord Jesus Christ. Mature Christians look forward in our spiritual race to press on toward the heavenly goal. (v15).
However, each christian is at different maturity in our walk with the Lord, do not try to impose the same expectation to every christians. We are to live up to what we have already attained (v16).
Citizen of heaven (v17-21)
Who are the enemies of the cross of Christ? (v18). Here are their descriptions: 1) their god is their stomach, 2) their glory is in their shame, 3) their mind is on earthly things.
Now, we need to evaluate ourselves against these descriptions and evaluate whether we live as enemies of the cross of Christ, or as citizen of heaven.