Shemot 19:20-22

Orthodox Jewish Bible

²⁰ And Hashem came down upon Mt. Sinai, onto the top of HaHar; and Hashem summoned Moshe up to the top of HaHar; and Moshe went up.

²¹ And Hashem said unto Moshe, Go down, warn HaAm, lest they push through toward Hashem to gaze, and many of them fall perishing.

²² And let the kohanim also, which come near to Hashem, set themselves apart as kodesh, lest Hashem break forth upon them.