1 Samuel 16:5

And he said, Peaceably: I am come to sacrifice unto the LORD: sanctify yourselves, and come with me to the sacrifice. And he sanctified Jesse and his sons, and called them to the sacrifice.

Sanctify yourselves - by the preparations described, Exodus 19:14. The elders were to sanctify themselves. Samuel himself took the greatest care in the sanctification of Jesse's family. Some, however, think that the former were invited only to join in the sacrifice, while the family of Jesse were invited by themselves to the subsequent feast.