Do not be anxious about anything, but in everything by prayer and supplication with thanksgiving let your requests be made known to God. And the peace of God, which surpasses all understanding, will guard your hearts and your minds in Christ Jesus.
In this passage, we are instructed not to be anxious about anything. Anything. In every circumstance, we can have the peace of God which surpasses all understanding, if we are thankful to Him. We can do this because we know He is in control and has promised to make all things work together for good (Romans 8:28),
It’s possible to cry out to God and still be in turmoil if we are not confident of His goodness. But when we ask God with a thankful heart, He will give us His peace. Praying with thankfulness for Who He is and the good He will do keeps us in God’s peace beyond what we can understand, no matter what our circumstances.