Exodus 19:23 WEB

²¹  Yahweh said to Moses, 'Go down, charge the people, lest they break through to Yahweh to gaze, and many of them perish.

²²  Let the priests also, who come near to Yahweh, sanctify themselves, lest Yahweh break forth on them.'

²³  Moses said to Yahweh, 'The people can't come up to Mount Sinai, for you charged us, saying, 'Set bounds around the mountain, and sanctify it.''

²⁴  Yahweh said to him, 'Go down and you shall bring Aaron up with you, but don't let the priests and the people break through to come up to Yahweh, lest he break forth on them.'

²⁵  So Moses went down to the people, and told them.