Exodus 33:9

The cloudy pillar descended - This very circumstance precluded the possibility of deception. The cloud descending at these times, and at none others, was a full proof that it was miraculous, and a pledge of the Divine presence. It was beyond the power of human art to counterfeit such an appearance; and let it be observed that all the people saw this, Exodus 33:10 . How many indubitable and irrefragable proofs of its own authenticity and Divine origin does the Pentateuch contain!