"Afterward, David was conscience-stricken for having cut off a corner of his robe" (1 Samuel 24:5).
Some insightful person wrote, "There is only one way to achieve happiness on this terrestrial ball,/And that is to have either a clear conscience, or none at all." David's clear and good conscience would not let him rest because he cut off a corner as proof of the power he could have had over Saul. God had assured David of the throne, and David's men interpreted this as a license to kill Saul while David had this blessed opportunity.
But David knew this wasn't a blessed time or place to commit any kind of sin. Even cutting a corner pierced David's conscience. Saul committed outrages against David but David knew that was no excuse to retaliate. Instead, David overcame evil with good (Romans 12:21). He reasoned with himself and his men that they should resist the temptation to take matters into their own hands, especially when they had such a grand opportunity to do so.
Perhaps the larger lesson here is the firm belief that our cause is in God's hands, the righteous Judge of all the earth; that He will not allow wrong to prevail over right in the end. This firm belief is the shield of faith we use to turn aside the darts of the terrible temptation to strike back when we feel hurt. We have no time for vindication, for that is God's time. We have no control over others' acts but we do have control over our reactions!
According to man's reasoning, David could have killed Saul and said he did it for the good of the nation. But David chose to interpret circumstances according to God's plan for all their lives, and was twice blessed with a good conscience and a throne that was not smeared with the blood of Saul, no matter how disgraceful Saul treated him. “Obedience stands severe tests when it withstands the temptation to take matters into one's own hands” (Anonymous).