Shemot 19:10-12

Orthodox Jewish Bible

¹⁰ So Hashem said unto Moshe, Go unto HaAm, and set them apart as kodesh today and tomorrow, and let them wash their clothing,

¹¹ And be ready by Yom HaShelishi; for Yom HaShelishi Hashem will come down in the sight of kol HaAm upon Mt. Sinai.

¹² And thou shalt set boundaries unto HaAm all around, saying, Take heed to yourselves, that ye go not up into HaHar, or touch the edge of it; whosoever toucheth HaHar shall be surely put to death;