All Israel from Dan even to Beersheba knew that Samuel was established to be a prophet of Yahweh.

Samuel said to Saul, "You have done foolishly. You have not kept the commandment of Yahweh your God, which he commanded you; for now Yahweh would have established your kingdom on Israel forever.

For as long as the son of Jesse lives on the earth, you shall not be established, nor your kingdom. Therefore now send and bring him to me, for he shall surely die!"

Now, behold, I know that you shall surely be king, and that the kingdom of Israel shall be established in your hand.