Saul said to the Kenites, Go, depart, get you down from among the Amalekites, lest I destroy you with them; for you shown kindness to all the children of Israel, when they came up out of Egypt. So the Kenites departed from among the Amalekites.
So Samuel is coming with a warning for him and telling him of a mission that God is sending him on. "Now hearken to the voice of the words of the Lord."