Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
You, no doubt, know the Talmudical saying, which includes in itself all the various kinds of interpretation connected with our subject. It runs thus:
[paragraph continues] "The Torah speaks according to the language of man," that is to say, expressions, which can easily be comprehended and understood by all, are applied to the Creator. Hence the description of God by attributes implying corporeality, in order to express His existence: because the multitude of people do not easily conceive existence unless in connection with a body, and that which is not a body nor connected with a body has for them no existence. Whatever we regard as a state of perfection, is likewise attributed to God, as expressing that He is perfect in every respect, and that no imperfection or deficiency whatever is found in Him. But there is not attributed to God anything which the multitude consider a defect or want; thus He is never represented as eating, drinking, sleeping, being ill, using violence, and the like. Whatever, on the other hand, is commonly regarded as a state of perfection is attributed to Him, although it is only a state of perfection in relation to ourselves; for in relation to God, what we consider to be a state of perfection, is in truth the highest degree of imperfection. If, however, men were to think that those human perfections were absent in God, they would consider Him as imperfect.
You are aware that locomotion is one of the distinguishing characteristics of living beings, and is indispensable for them in their progress towards perfection. As they require food and drink to supply animal waste, so they require locomotion, in order to approach that which is good for them and in harmony with their nature, and to escape from what is injurious and contrary to their nature. It makes, in fact, no difference whether we ascribe to God eating and drinking or locomotion; but according to human modes of expression, that is to say, according to common notions, eating and drinking would be an imperfection in God, while motion would not, in spite of the fact that the necessity of locomotion is the result of some want. Furthermore, it has been clearly proved, that everything which moves is corporeal and divisible; it will be shown below that God is incorporeal and that He can have no locomotion; nor can rest be ascribed to Him; for rest can only be applied to that which also moves. All expressions, however, which imply the various modes of movement in living beings, are employed with regard to God in the manner we have described and in the same way as life is ascribed to Him: although motion is an accident pertaining to living beings, and there is no doubt that, without corporeality, expressions like the following could not be imagined: "to descend, to ascend, to walk, to place, to stand, to surround, to sit, to dwell, to depart, to enter, to pass, etc.
It would have been superfluous thus to dilate on this subject, were it not for the mass of the people, who are accustomed to such ideas. It has been necessary to expatiate on the subject, as we have attempted, for the benefit of those who are anxious to acquire perfection, to remove from them such notions as have grown up with them from the days of youth.