As to the nature of angels, they are described, (1.) As pure spirits, i.e., immaterial and incorporeal beings. The Scriptures do not attribute bodies of any kind to them. On the assumption that spirit unconnected with matter cannot act out of itself, that it can neither communicate with other spirits nor operate on the external world, it was maintained by many, and so decided in the council held at Nice, A.D. 784, that angels had bodies composed of ether or light; an opinion which was thought to be favoured by such passages as Matt. xxviii. 8, Luke ii. 9, and other passages in which their luminous appearance and the glory attending ther presence are spoken of. The Council of Lateran, A.D. 1215, decided that they were incorporeal, and this has been the common opinion in the Church. They are declared to be "substantiæ spirituales, omnis corporeæ molis expertes." As such, therefore, they are invisible, incorruptible, and immortal. Their relation to space is described as an illocalitas; not ubiquity or omnipresence, as they are always somewhere and not everywhere at any given moment, but they are not confined to space circumscriptively as bodies are, and can move from one portion of space to another. As spirits they are possessed of intelligence, will, and power. With regard to their knowledge, whether as to its modes or objects, nothing special is revealed. All that is clear is that in their intellectual faculties and in the extent of their knowledge they are far superior to man. Their power also is very great, and extends over mind and matter. They have the power to communicate one with another and with other minds, and to produce effects in the natural world. The greatness of their power is manifest, (a.) From the names and titles given to them, as principalities, powers, dominions, and world-rulers. (b.) From the direct assertions of Scripture, as they are said to "excel in strength;" and (c.) From the effects attributed to their agency. However great their power may be, it is nevertheless subject to all the limitations which belong to creatures. Angels, therefore, cannot create, they cannot change substances, they cannot alter the laws of nature, they cannot perform miracles, they cannot act without means, and they cannot search the heart; for all these are, in Scripture, declared to be prerogatives peculiar to God. The power of angels is, therefore, (1.) Dependent and derived. (2.) It must be exercised in accordance with the laws of the material and spiritual world. (3.) Their intervention is not optional, but permitted or commanded by God, and at his pleasure, and, so far as the external world is concerned, it would seem to be only occasional and exceptional. These limitations are of the greatest practical importance. We are not to regard angels as intervening between us and God, or to attribute to them the effects which the Bible everywhere refers to the providential agency of God.
Hodge v 1 p. 637-638