In Matt 6, Jesus teaches about relief from anxiety in a sermon in which He first teaches us how to pray. In Eph 6, Paul links standing fast in spiritual warfare through prayer. In Phil 4, Paul brings these themes together. The overarching admonition in Philippians is to stand firm against all opposition (Phil 1:27-30, 4:1). One of the ways we do this is by being anxious for nothing while making everything a matter of prayer (Phil 4:6). The remedy for anxiety is to commitment those concerns to God in prayer with a thankful heart, recognizing our lowliness and His sufficiency. Paul also tells us to be specific in our requests. This is what it means to cast our worries on God for He cares for us (1 Pet 5:7).