I Samuel 16:1-3

Now the LORD said to Samuel, “How long will you mourn for Saul, seeing I have rejected him from reigning over Israel? Fill your horn with oil, and go; I am sending you to Jesse the Bethlehemite. For I have provided Myself a king among his sons.” And Samuel said, “How can I go? If Saul hears it, he will kill me.” But the LORD said, “Take a heifer with you, and say, ‘I have come to sacrifice to the LORD.’ Then invite Jesse to the sacrifice, and I will show you what you shall do; you shall anoint for Me the one I name to you.”