4Paul counsels the Philippian believers to to be anxious about anything (4:6), but instead to channel their worries into prayer. We need to let our troubles be God's concerns...easier said than done. But if anyone ever had cause for worry, it was Paul, facing a Roman judge for treason, disloyalty to Caesar (for insisting that Christ alone was Lord).
Worry becomes a form of atheism because it tries to manage life apart from God. Or we could say that worry is praying to the wrong god. Regardless of what we claim to believe, when we worry we are practicing a subtle form of distrust in God. And it becomes a fear that can paralyze us. Anxiety ought to be a reminder for us to pray. God is handling our troubles and doesn't need our help. "In quietness and confidence shall be your strength" says Isaiah (30:15). Worry is SIN in that it is questioning God's love and purpose. Prayer combats worry by building trust. By spending time with God we take a break from our cares and gradually gain peace and learn serenity.