Exodus 19:10

19:10 The Lord said to Moses, “Go to the people and sanctify them today and tomorrow, and make them wash their clothes

Exodus 19:15

19:15 He said to the people, “Be ready for the third day. Do not go near your wives.”

Exodus 19:22

19:22 Let the priests also, who approach the Lord, sanctify themselves, lest the Lord break through against them.”