1 Samuel 16:5

And he said, Peaceably, he had no special occasion to rebuke them; I am come to sacrifice unto the Lord; sanctify yourselves, and come with me to the sacrifice, the celebration being intended to strengthen the people's fellowship with Jehovah. And he sanctified Jesse and his sons, addressing this admonition to them in particular, so they would be sure to wash themselves and put on clean garments, and called them to the sacrifice, as his own special guests.