The following article is from Joyce Meyer. Her message is that our outlook can help to determine our stress level.
Practical Tips On Reducing Stress
26   Look at the birds in the sky: They do not sow, or reap, or gather into barns, yet your heavenly Father feeds them. Aren't you more valuable than they are?
27   And which of you by worrying can add even one hour to his life? (Matthew 6:26-27 .NET Bible)