1 Samuel 16:1-3

Now the Lord said to Samuel, “How long are you going to mourn for Saul, since I have rejected him from being king over Israel? Fill your horn with oil and go; I will send you to Jesse the Bethlehemite, because I have chosen a king for Myself among his sons.”

But Samuel said, “How can I go? When Saul hears about it, he will kill me.” But the Lord said, “Take a heifer with you and say, ‘I have come to sacrifice to the Lord.’

And you shall invite Jesse to the sacrifice, and I will let you know what you shall do; and you shall anoint for Me the one whom I designate to you.”