A Psalm of David.
Do not fret because of evildoers,
Nor be envious of the workers of iniquity.
In Hebrew the word fret is associated with anger and envy.
Basically when we fret we are inclined towards getting hot and fiery.
There is plenty of material in daily life that we can "fret" about.
Strangely, the Hebrew word picture for fret is: "to separate a person to reveal".
When you get hot and fiery you are not a person others want to be around.
So, next time you "fret" and suddenly find yourself alone, calm yourself and check the state of your heart.
Could be your fretting has revealed your level of distrust in the Lord's ability to work in and through all your circumstances.
Do not fret, rather be thankful that Father is working all things together for good.