Then Saul said to Samuel, "I have sinned. I violated the LORD's command and your instructions. I was afraid of the people and so I gave in to them. Now I beg you, forgive my sin and come back with me, so that I may worship the LORD."
But Samuel said to him, "I will not go back with you. You have rejected the word of the LORD, and the LORD has rejected you as king over Israel!" 1 Samuel 15:24-26
Just like that his favor with the Lord was over. That had to come to Saul as a total shock. It's one thing for a man to reject you, but it's something entirely different when the God you worship rejects you as leader.
The things we do in life have consequences. Yes, we can receive forgiveness for those actions, but they still have consequences. If you speed down the highway and get a speeding ticket, that is just the beginning of the natural consequences for your violation of the law. You still have to pay the fine, incur driving points, and pay higher insurance rates for three years. If you plead for mercy on the court, you'll get a smiley face on your ticket for confessing, but you'll still have to pay the penalties for your actions. The consequences for what you've done are still there. Saul realized his sin, confessed it, but the damage was already done to his leadership.
I think it's a solemn reminder to us that we live in a fallen world. Every day we see the consequences of living without God. We see violence, destruction, and chaos. We see broken homes and broken dreams. We see men and women get away with crimes they've committed. God forgives us when we come to him, but we still must make a difference in the world.
And it should be said that righteous actions also have consequences.