Observation: For the second time, while Saul has brought his army to hunt down and kill David, David has instead had an opportunity to easily kill Saul but has refused. Both times, David has something of Saul's to prove that he was right there, inches from Saul, with a murderous weapon in hand, and spared him. This time, what he has is Saul's own spear that was next to him while he slept.
Saul declares his actions sin, that David is the greater man for sparing his life, and that he will not pursue David anymore, but David knows he is lying because he's made these same declarations before. One way David could permanently remind Saul of his declarations is by ... keeping Saul's spear. In so doing, every time Saul went anywhere with his men, he would be missing is own primary weapon - likely the weapon he liked the best since it was the one he kept near him in his sleep - and that would remind Saul that David has the spear, David spared his life, and David is not his enemy. David doesn't do this. He leaves the spear and tells Saul to have someone come and retrieve it. The obvious reason is that taking Saul's spear is stealing, which violates God's law.
David could have killed Saul, which would have been justified as Saul is actively trying to kill David, but he won't because that violates the Lord's anointing of Saul as king. David could keep Saul's spear as a reminder and perhaps long-term protection of himself, but he won't because that violates the Lord's commandment to not steal. Instead, David will now have to move to a foreign-occupied land, with hardship to his friends and all their families, but that is not a sin so that is what he will do.
Application: David is an example of someone who is trying to do what is right by the Lord in all circumstances, even to the point that he will not do that which is obviously justified - just keep Saul's spear as a reminder or symbol - because that violates the law. And yes, David isn't perfect and commits sin, but he is striving to find a path to a good outcome while remaining aligned to the Lord.
This is important as we consider issues of religious conflict. Even if others are violent ... even if others curse at us ... even if others oppress Christians personally and professionally ... we must resist without committing even lesser sins. This is what allows room for the Lord to act in such circumstances.
Prayer: Lord, as I continue to ponder the ideas of the radical liberalism in our area and how it now is manifesting as open opposition to Christianity, may we all be reminded that we must not respond with even lesser sinful acts and words. You will take care of the situation as we simply honor you. Amen.