Be anxious for nothing, but in everything by prayer and supplication, with thanksgiving, let your requests be known to God; (7) and the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus. (8) Finally, brethren, whatever things are true, whatever things are noble, whatever things are just, whatever things are pure, whatever things are lovely, whatever things are of good report, if there is any virtue and if there is anything praiseworthy – meditate on these things. (9) The things which you learned and received and heard and saw in me, these do, and the God of peace will be with you.

The letter to the Philippians was written by the apostle Paul while imprisoned in Rome for preaching the gospel. Our verses today exhort the Philippians to cast their cares on the Lord – to use prayer to fight anxiety which proceeds from distrust of divine help. The peace of God – mentioned only here in the New Testament – does not depend on the present aspect of things or on the shifting of the world but on confidence in the sovereignty of God; that the good will of God will be the grand sum of our desires. Paul advises prayer with thanks for every concern and peace is what we are promised. In God’s peace, in this joy, we are effective witnesses to Christ Jesus. Because of Christ we can go directly to God – prayer is not for God’s sake but for ours.
Our prayer must be in line with God’s purpose and will; if something makes us anxious it’s not trivial and prayer with thanksgiving makes us calm until we get through crisis. Verses 8 and 9 are connected as our thought life forms the basis for our behavior. Our conduct flows from genuine conversion and rebirth in faith in Christ as we begin our process of sanctification. The emotional result of this process is that the peace of God will be with us. This is not a modification of our thoughts and our will is not merely adding something to our lives but it is change at the core of our being. It is not mere intellectual understanding. It a change of heart – true biblical change. We must respond with our will as the lordship of Christ enters every aspect of our lives. Without Christ we have only our stubborn self will which never gives us peace.
To maintain tranquility rather than becoming distraught, we should take our worries to God and replace worry with prayer. Paul is talking in our verses of peace FROM God, not peace WITH God which acts as a sort of sentry to guard (and guide) our hearts and minds. The promise here is that if we pray, with thanksgiving rather than worry, God will give us peace. I’m reminded of how we close many meetings of Alcoholics Anonymous when we say “keep coming back; it works if you work it”. Make Prayer your substitution for worry.