But seek first his kingdom and his righteousness, and all these things will be given to you as well.  Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.
(Matthew 6:33-34)

I've used this scripture before.  It's one that I know is true, yet I can't seem to let go of worry.  Just like it says, life is rough enough without adding worry to the mix.  Worry is a worthless waste of energy and actually damaging to my peace of mind as well as my relationship with God.  If I am granted a tomorrow, God will walk with me and guide me through anything that comes my way, good or bad.  So....worry not!