出埃及记 19:9

耶和华对摩西说：「我要在密云中临到你那里，叫百姓在我与你说话的时候可以听见，也可以永远信你了。」于是，摩西将百姓的话奏告耶和华。

And the LORD said unto Moses, Lo, I come unto thee in a thick cloud, that the people may hear when I speak with thee, and believe thee for ever. And Moses told the words of the people unto the LORD.