Philippians 4:6-7 (emphasis mine) says,
"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."
It's so easy to say that I believe Scripture is true. When a first-rate worrier is told not to "be anxious about anything," the last thing they want to do is say, "Okay. You're right. I'm going to praise God and let it go!"
There's a backwards desire in me to want to be worried. If I'm not wringing my hands about something, I think I'm probably making a million hidden mistakes. For example, if I'm not hounding myself about doing better in school, I'm probably letting my grades go to pot. If I'm not chastising myself over completing some kind of Christian checklist (so very easy to make), I'm probably sinning left and right without even noticing.
Lately, I've been quoting this Philippians verse to myself whenever I feel that inexorable pull towards being paranoid.
I've found--unsurprisingly, I suppose--that when I do, God gives me a peace that I could never conjure on my own. Trust me, that's thorough proof that God does the impossible every day in the lives of "normal" people.
Well, as Chris will attest, I can't exactly classify myself as normal... ;)