Charles H. Spurgeon on Psalms 121:6

Nor the moon by night. In the cloudless skies of the East, where the moon shines with such exceeding clearness, its effects upon the human frame have been found most injurious. The inhabitants of these countries are most careful in taking precautionary measures before exposing themselves to its influence. Sleeping much in the open air, they are careful to cover well their heads and faces. It has been proved beyond a doubt that the moon smites as well as the sun, causing blindness for a time, and even distortion of the features. Sailors are well aware of this fact; and a naval officer relates that he has often, when Sailing between the tropics, seen the commanders of vessels waken up young men who have fallen asleep in the moonlight. Indeed, he witnessed more than once the effects of a moonstroke, when the mouth was drawn on one side and the sight injured for a time. He was of opinion that, with long exposure, the mind might become seriously affected. It is supposed that patients suffering under fever and other illnesses are affected by this planet, and the natives of India constantly affirm that they will either get better or worse, according to her changes. —C.W., in, "The Biblical Treasury."