Question: We are studying angels in a Bible study at our church....

Question: We are studying angels in a Bible study at our church. The question of who or what demons are came up and the teacher said that they are not fallen angels. We were under the impression that they are. Your help would be most appreciated.

Response: We agree with you that demons are fallen angels. That conclusion cannot be avoided, particularly since we know that Satan was once an angel (Isaiah:14:12-15 [12] How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! [13] For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: [14] I will ascend above the heights of the clouds; I will be like the most High. [15] Yet thou shalt be brought down to hell, to the sides of the pit.
See All...; Ezekiel:28:14-17 [14] Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire. [15] Thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee. [16] By the multitude of thy merchandise they have filled the midst of thee with violence, and thou hast sinned: therefore I will cast thee as profane out of the mountain of God: and I will destroy thee, O covering cherub, from the midst of the stones of fire. [17] Thine heart was lifted up because of thy beauty, thou hast corrupted thy wisdom by reason of thy brightness: I will cast thee to the ground, I will lay thee before kings, that they may behold thee.
See All...), is a spirit being, and has been called the tempter, the adversary, that great dragon, and other similar titles. Further, according to Scripture, angels are spirit beings, intelligent, and have wills. They have personalities and are immortal and powerful.

The Scriptures also speak of fallen angels (Matthew:25:41Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:
See All...; Revelation:12:7-9 [7] And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, [8] And prevailed not; neither was their place found any more in heaven. [9] And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
See All...). “And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.” When God created angels, they were “good” because all creation was good (Genesis:1:31And God saw every thing that he had made, and, behold, it was very good. And the evening and the morning were the sixth day.
See All...). The King James Version uses the word “devils” to describe these demonic beings who are commonly called “demons” in other translations.

With this in mind, the Lord Jesus said in Matthew:25:41Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:
See All...: “Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels.”

Speaking of Satan, Paul described him in Ephesians:2:2Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:
See All... as a spirit who works within “the children of disobedience.” In the New Testament, a number of cases of demonic possession or oppression are highlighted.

The Scriptures warn us concerning the devil and his tactics. Second Corinthians 11:13-15 reveals that one of the adversary’s favorite roles is to present himself as an angel of light. Paul further warned us in Galatians:1:8But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
See All... that, “...though we, or an angel from heaven preach any other gospel unto you than that which we have preached unto you, let him be accursed.” Devils (demons) are fallen angels.