Then Samuel took the horn of oil, and anointed him in the midst of his brothers: and the Spirit of Yahweh came mightily on David from that day forward. So Samuel rose up, and went to Ramah.
Now that shows you how far Saul has strayed from the Lord, and the things of the Lord, he would actually kill the prophet of God. Samuel realized this, "This guy is really gone off the deep end. Lord if he hears I'm going to go down and anoint another king, he's gonna kill me."