Paul says not to be anxious about anything, but to make requests known to God by prayer and supplication with thanksgiving: Philippians 4:6. He says the peace of God will guard hearts and minds in Christ Jesus: Philippians 4:7.
In Philippians 4:4–7, Paul gives a short chain of instructions meant to shape the community’s emotional tone and public posture. He calls them to keep rejoicing “in the Lord,” to let a noticeable gentleness mark how others experience them, and to replace anxiety with prayer that includes thanksgiving. These lines sit in the closing stretch of the letter where Paul moves from earlier appeals about shared mindset and unity into brief, memorable directions for daily life. Just before this, he has urged certain people to agree and has addressed the community’s support network (see Philippians 4:2–3).
Paul strings together short directions that aim at the community’s tone and posture: ongoing joy, visible gentleness, and anxiety being displaced by prayer that includes thanks (Philippians 4:4–4:6).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Philippians 4:6, then read the surrounding section so the answer stays connected to the passage's flow.
6In nothing be anxious, but in everything, by prayer and petition with thanksgiving, let your requests be made known to God.