Exodus 19:21-25

²¹Then the Lord spoke to Moses: “Go down, warn the people, so that they do not break through to the Lord to stare, and many of them perish. ²²Also have the priests who approach the Lord consecrate themselves, or else the Lord will break out against them.” ²³And Moses said to the Lord, “The people cannot come up to Mount Sinai, for You warned us, saying, ‘Set boundaries around the mountain and consecrate it.’ ” ²⁴Then the Lord said to him, “Go down and come up again, you and Aaron with you; but do not let the priests and the people break through to come up to the Lord, or He will break out against them.” ²⁵So Moses went down to the people and told them.