I believe, proclaim and teach: that Lucifer is an actual being that was once right with the Living God; through pride, selfish ambition, he betrayed God and as a result, The Lord brought down upon his head eternal judgment. He operates today as the god of this world and the prince of the power of the air amongst other descriptives. He is the deceiver of the nations, and the father of all lies; he is the enemy and opposer of fallen mankind. However… He[Jesus] had disarmed the rulers and authorities [those supernatural forces of evil operating against us], He made a public example of them [exhibiting them as captives in His triumphal procession], having triumphed over them through the cross. Colossians 2:15 AMP… Jesus defeated him and made him a spectacle. He shall be thrown into the lake of fire which is the eternal place of punishment prepared for the devil and all who follow him.
Isaiah 14:12-15
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! 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: I will ascend above the heights of the clouds; I will be like the most High. Yet thou shalt be brought down to hell, to the sides of the pit.
Jude 6
And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day.
1 John 3:8
He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
Ezekiel 28:14-17
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.;
1 Peter 5:8
Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:
John 8:43-44
Why do ye not understand my speech? even because ye cannot hear my word. Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
The Devil is a "them" not a "him". The reason why we see the word "him" is about authority. When a general or a king enters the battle we traditionally do not say that: "such and such army" entered the battle of such and such. No, they will just say the general's or the kings name and "He" did this or that. He himself probably never lifted a finger or drew a sword --- His army did the actual work.
So, when someone mocks Christianity about a Devil going around causing problems, They just do not understand good biblical theology.
The Devil is like the Mafia. They have capos (captains) or leaders. And there is a hierarchy. Often you will hear me refer to the Devil as a Mafia to convey to those who think there is one entity causing all the chaos in the world; I'll explain that the phrase the Devil is not Lucifer's personal pronoun. It is a job descriptive of what he and his cohorts do --- which is to "tear apart". That is what the Devil means. Just like when you hear the phrase the Mafia, one doesn't think of just one person. They think of multiple people operating as a force to perform criminal acts. The Devil, like the Mafia is not just one person or entity. Its a hierarchy of entities that is organizational by levels of wickedness. And the chief prince is Lucifer, a morning star angel, we read about earlier in Job 38.
Then one may ask what is Satan? Satan is just the Hebrew form of the Devil --- the ones who tear a part. This reflects the spiritual warfare we see in Daniel.