Here’s a key difference between Saul and David: they both sinned, but David knew how to repent, whereas Saul didn’t.
David took his sin seriously, Saul throughout this chapter was making excuses or downright lying about breaking the Lord’s command.
David went on to be called a man after God’s own heart. Saul has gone down in history as the man God regretted anointing as king.
Getting our repentance right matters.