The Bible is the only source book of knowledge about the angels. Nearly three hundred times they are mentioned as actual though spiritual beings. Their realm is a heavenly one above the sphere of men (Ps. 8:4-5; Heb. 2:7)
Evidently the angels were created long before man for we find them present at creation (Job 38:7). Their nature is that of ministering spirits first to God, and then to the people of God (Heb.1:14). They are always referred to in the masculine gender although we believe them to be sexless and not increased by generation. Their number is "an innumerable company: or "myriads" (Heb. 12:22; Rev. 5:11).
Of the holy angels two are mentioned in particular, as well as several classes. Michael is one whose name means "who is like unto God: and who seems to have had responsibility concerning the Jewish people (Dan. 10:21; 12:1; Jude 9). Gabriel is another whose name means "the mighty one" and to whom has been entrusted a number of important missions (Dan. 8:16; Luke 1:19; Luke 1:26-28).
The class of angels known as the Cherubim seems to have been given the responsibility of defending God's holiness from the pollution of sinful beings (Gen. 3:24; Exod. 25:17-20). Another class is that of Seraphim who evidently were similarly used (Isa. 6:2-7).
The title "The Angel of Jehovah" belongs to God and is used in connection with divine manifestations in the earth and is, therefore, not included in the angelic hosts.
As well as being messengers of God, and ministers (God's servants) to Christians, the angels are evidently spectators and witnesses of the things that take place on earth (Ps. 103:20; Luke 12:8-9; 15:10).
The fallen angels are divided into two classes: those who are free and those who are bound (Jude 6). It is probable that when Satan fell, he drew after him a multitude of lesser angelic beings. These are known as demons in the Scriptures. They are Satan's aides in all his diabolical undertakings and will share his coming doom (Mark 5:9; I Tim. 4:1; Matt. 25:41; Rev. 20:10).
Copied for WholesomeWords.org from Believer's First Bible Course by William W. Orr. Wheaton, Ill.: Scripture Press, 1956.