From Oswald Chambers:
Do not fret— it only causes harm —Psalm 37:8
Worrying always results in sin. We tend to think that a little anxiety and worry are simply an indication of how wise we really are, yet it is actually a much better indication of just how wicked we are. Fretting rises from our determination to have our own way. Our Lord never worried and was never anxious, because His purpose was never to accomplish His own plans but to fulfill God’s plans. Fretting is wickedness for a child of God.
Have you been propping up that foolish soul of yours with the idea that your circumstances are too much for God to handle? Set all your opinions and speculations aside and “abide under the shadow of the Almighty” (Psalm 91:1). Deliberately tell God that you will not fret about whatever concerns you. All our fretting and worrying is caused by planning without God.