This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Angel (Gr. a messenger), a name given in Jewish and Christian theology to certain spiritual beings endowed with superhuman powers of intelligence and of will. They are frequently mentioned in the Old as well as the New Testament as immediate instruments of Divine Providence. In Scripture, however, the original word not unfrequently has its primary signification of messenger, even where rendered angel in the Vulgate and the English version. They are regarded as pure spirits in whose existence there is nothing material. They often appear in the Scriptures with bodies and in the human form; but it was in the early church and still is a matter of theological dispute whether these bodies and this form were only assumed by them for a time for the special purpose of conversing with men. Besides these good angels, the church recognizes a class of "fallen angels," who left their first estate and are now "angels of the devil." The second council of Constantinople, contrary to the opinion of Ori-gen, declared that there are different classes of angels; and since Dionysius the Areopagite the opinion that there are nine classes of angels has become prevalent in the Catholic and eastern churches.
It was a common opinion among the fathers of the early Christian church that every individual is under the care of a particular angel who is assigned to him as a guardian; but Protestant theology finds nothing in the Bible to support this notion. While the older Protestant churches, in general, agree in the doctrine of the angels with the Catholic and eastern churches, they reject as unbiblical the opinion of the latter that it is good and useful to ask the good angels for their protection, aid, and intercession, and to venerate their images. According to the critical school of Protestant theology, the belief in angels was foreign to the early religion of the Jews, and derived from the Persians about the time of the Babylonish captivity. Sev-cral prominent Protestant theologians of modern times, like Schleiermacher and Hase, deny the existence of angels altogether, regarding them as creatures of Biblical poetry; others, like Martensen and Rothe, endeavor to establish the doctrine on a new speculative basis; while Swedenborg and his followers regard the angels of the Bible and all spiritual creatures as disembodied human beings, who have at some time existed in the flesh in this or some other world. (See New Jerusalem Church.) Pictures of the angels were expressly allowed by the second council of Nice. They are usually represented in the human form, in the male sex, as beautiful youths; the rapidity with which they are supposed to carry out the commands of God is symbolized by wings, flowing garments, and naked feet; harps and other musical instruments which are placed in their hands are intended to indicate that they incessantly sing the praise of God.