Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
As for the existence of angels, there is no necessity to cite any proof from Scripture, where the fact is frequently mentioned. The term elohim signifies "judges"; comp. "The cause of both parties shall come before the 'judges'" (ha-elohim; Exod. xxii. 8). It has been figuratively applied to angels, and to the Creator as being judge over the angels. When God says, "I am the Lord your God," the pronoun "your" refers to all mankind; but in the phrase elohe ha-elohim, He is described as the God of the angels, and in adone ha-adonim, as the Lord of the spheres and the stars, which are the masters of the rest of the corporeal creation. The nouns elohim and adonim in these phrases do not refer to human judges or masters, because these are in rank inferior to the heavenly bodies: much less do they refer to mankind in general, including masters and servants, or to objects of stone and wood worshipped by some as gods; for it is no honour or greatness to God to be superior to stone, wood, or a piece of metal. The phrases therefore admit of no other meaning than this: God is the judge over the judges; i.e., over the angels, and the Lord over the spheres.
We have already stated above that the angels are incorporeal. This agrees with the opinion of Aristotle: there is only this difference in the names employed--he uses the term "Intelligences," and we say instead "angels." His theory is that the Intelligences are intermediate beings between the Prime Cause and existing things, and that they effect the motion of the spheres, on which motion the existence of all things depends. This is also the view we meet with in all parts of Scripture: every act of God is described as being performed by angels. But "angel" means "messenger"; hence every one that is intrusted with a certain mission is an angel. Even the movements of the brute creation are sometimes due to the action of an angel, when such movements serve the purpose of the Creator, who endowed it with the power of performing that movement; e.g., "God hath sent His angel, and hath shut the lions' mouths that they have not hurt me" (Dan. vi. 22). Another instance may be seen in the movements of Balaam's ass, described as caused by an angel. The elements are also called angels. Comp. "Who maketh winds His angels, flaming fire His ministers" (Ps. civ. 4). There is no doubt that the word "angel" is used of a messenger sent by man; e.g., "And Jacob sent angels" (Gen. xxxii. 4); of a prophet, e.g., "And an angel of the Lord came up from Gilgal to Bochim" (Judges ii. 1); "And He sent an angel, and hath brought us forth out of Egypt" (Num. xx. 16). It is also used of ideals, perceived by prophets in prophetic visions, and of man's animal powers, as will be explained in another place.
When we assert that Scripture teaches that God rules this world through angels, we mean such angels as are identical with the Intelligences. In some passages the plural is used of God, e.g., "Let us make man in our image" (Gen. i. 26); "Go to, let us go down, and there confound their language" (ibid. xi. 7). Our Sages explain this in the following manner: God, as it were, does nothing without contemplating the host above. I wonder at the
expression "contemplating," which is the very expression used by Plato: God, as it were, "contemplates the world of ideals, and thus produces the existing beings." In other passages our Sages expressed it more decidedly: "God does nothing without consulting the host above" (the word familia, used in the original, is a Greek noun, and signifies "host"). On the words, "what they have already made" (Eccles. ii. 12), the following remark is made in Bereshit Rabba and in Midrash Koheleth: "It is not said 'what He has made,' but 'what they have made'; hence we infer that He, as it were, with His court, have agreed upon the form of each of the limbs of man before placing it in its position, as it is said, 'He hath made thee and established thee'" (Deut. xxxii. 6). In Bereshit Rabba (chap. li.) it is also stated, that wherever the term "and the Lord" occurred in Scripture, the Lord with His court is to be understood. These passages do not convey the idea that God spoke, thought, reflected, or that He consulted and employed the opinion of other beings, as ignorant persons have believed. How could the Creator be assisted by those whom He created! They only show that all parts of the Universe, even the limbs of animals in their actual form, are produced through angels: for natural forces and angels are identical. How bad and injurious is the blindness of ignorance! Say to a person who is believed to belong to the wise men of Israel that the Almighty sends His angel to enter the womb of a woman and to form there the fœtus, he will be satisfied with the account; he will believe it, and even find in it a description of the greatness of God's might and wisdom; although he believes that the angel consists of burning fire, and is as big as a third part of the Universe, yet he considers it possible as a divine miracle. But tell him that God gave the seed a formative power which produces and shapes the limbs, and that this power is called "angel," or that all forms are the result of the influence of the Active Intellect, and that the latter is the angel, the Prince of the world, frequently mentioned by our Sages, and he will turn away; because he cannot comprehend the true greatness and power of creating forces that act in a body without being perceived by our senses. Our Sages have already stated--for him who has understanding--that all forces that reside in a body are angels, much more the forces that are active in the Universe. The theory that each force acts only in one particular way, is expressed in Bereshit Rabba (chap. 1.) as follows: "One angel does not perform two things, and two angels do not perform one thing"; this is exactly the property of all forces. We may find a confirmation of the opinion that the natural and psychical forces of an individual are called angels in a statement of our Sages which is frequently quoted, and occurs originally in Bereshit Rabba (chap. lxxviii.): "Every day God creates a legion of angels; they sing before Him, and disappear." When, in opposition to this statement, other statements were quoted to the effect that angels are eternal--and, in fact, it has repeatedly been shown that they live permanently--the reply has been given that some angels live permanently, others perish; and this is really the case; for individual forces are transient, whilst the genera are permanent and imperishable. Again, we read (in Bereshit Rabba, chap. lxxxv.), in reference to the relation between Judah and Tamar: "R. Jochanan said that Judah was about to pass by [without noticing Tamar], but God caused the angel of lust, i.e., the libidinous disposition, to present himself to him." Man's disposition is here called
an angel. Likewise we frequently meet with the phrase "the angel set over a certain thing.'' In Midrash-Koheleth (on Eccles. x. 7) the following passage occurs: "When man sleeps, his soul speaks to the angel, the angel to the cherub." The intelligent reader will find here a clear statement that man's imaginative faculty is also called "angel," and that "cherub" is used for man's intellectual faculty. How beautiful must this appear to him who understands it; how absurd to the ignorant!
We have already stated that the forms in which angels appear form part of the prophetic vision. Some prophets see angels in the form of man, e.g., "And behold three men stood by him" (Gen. xviii. 2); others perceive an angel as a fearful and terrible being, e.g., "And his countenance was as the countenance of an angel of God, very terrible" (Judges xiii. 6); others see them as fire, e.g., "And the angel of the Lord appeared to him in a flame of fire" (Exod. iii. 2). In Bereshit Rabba (chap. l.) the following remark occurs: "To Abraham, whose prophetic power was great, the angels appeared in the form of men; to Lot, whose power was weak, they appeared as angels." This is an important principle as regards Prophecy; it will be fully discussed when we treat of that subject (chap. xxxii. sqq.). Another passage in Bereshit Rabba (ibid.) runs thus: "Before the angels have accomplished their task they are called men, when they have accomplished it they are angels." Consider how clearly they say that the term "angel" signifies nothing but a certain action, and that every appearance of an angel is part of a prophetic vision, depending on the capacity of the person that perceives it.
There is nothing in the opinion of Aristotle on this subject contrary to the teaching of Scripture. The whole difference between him and ourselves is this: he believes all these beings to be eternal, co-existing with the First Cause as its necessary effect; but we believe that they have had a beginning, that God created the Intelligences, and gave the spheres the capacity of seeking to become like them: that in creating the Intelligences and the spheres, He endowed them with their governing powers. In this point we differ from him.
In the course of this treatise we shall give his theory as well as the theory of Creatio ex nihilo taught in Scripture.