Shemot 19:21-23

Orthodox Jewish Bible

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.

²³ And Moshe said unto Hashem, HaAm cannot come up to Mt. Sinai; for You Yourself charged us, saying, Establish boundaries for HaHar, and set it apart as kodesh.