David has had opportunity after opportunity to kill Saul. Verse 9 says
8 Keep me as the apple of your eye;
hide me in the shadow of your wings
9 from the wicked who are out to destroy me,
from my mortal enemies who surround me.
But David knows: verse (go back to verse 3)
Though you probe my heart,
though you examine me at night and test me,
you will find that I have planned no evil;
my mouth has not transgressed.
IN ALL circumstances…ALL David says:
The first 8 verses are worth reading out loud!