Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
THE corporeal element in man is a large screen and partition that prevents him from perfectly perceiving abstract ideals: this would be the case even if the corporeal element were as pure and superior as the substance of the spheres; how much more must this be the case with our dark and opaque body. However great the exertion of our mind may be to comprehend the Divine Being or any of the ideals, we find a screen and partition between Him
and ourselves. Thus the prophets frequently hint at the existence of a partition between God and us. They say He is concealed from us in vapours, in darkness, in mist, or in a thick cloud: or use similar figures to express that on account of our bodies we are unable to comprehend His essence. This is the meaning of the words, "Clouds and darkness are round about Him" (Ps. xcvii. 2). The prophets tell us that the difficulty consists in the grossness of our substance: they do not imply, as might be gathered from the literal meaning of their words, that God is corporeal, and is invisible because He is surrounded by thick clouds, vapours, darkness, or mist. This figure is also expressed in the passage, "He made darkness His secret place" (Ps. xviii. 12). The object of God revealing Himself in thick clouds, darkness, vapours, and mist was to teach this lesson; for every prophetic vision contains some lesson by means of allegory; that mighty vision, therefore, though the greatest of all visions, and above all comparison, viz., His revelation in a thick cloud, did not take place without any purpose, it was intended to indicate that we cannot comprehend Him on account of the dark body that surrounds us. It does not surround God, because He is incorporeal. A tradition is current among our people that the day of the revelation on Mount Sinai was misty, cloudy, and a little rainy. Comp. "Lord, when thou wentest forth from Seir, when thou marchedst out of the field of Edom, the earth trembled, and the heavens dropped water" (Judges v. 4). The same idea is expressed by the words "darkness, clouds, and thick darkness" (Deut. iv. 11). The phrase does not denote that darkness surrounds God, for with Him there is no darkness, but the great, strong, and permanent light, which, emanating from Him, illuminates all darkness, as is expressed by the prophetic simile, "And the earth shined with His glory" (Ezek. xliii. 2).