Exodus 19:10, 15, 22

And Jehovah said unto Moses, Go unto the people, and sanctify them to-day and to-morrow, and let them wash their garments

And he said unto the people, Be ready against the third day: come not near a woman.

And let the priests also, that come near to Jehovah, sanctify themselves, lest Jehovah break forth upon them.