3 Bible Tips: Demons
"The fallen angels, hostile to God and men, are called demons in the Bible. They share with Satan, their leader, the goal of deceiving people with false doctrine, generally making human life miserable and, if possible, even destroying people" ("Is There Really a Spirit World?").
1. Perhaps a third of the angels followed Lucifer in his rebellion against God. These fallen angels we call demons.
"And another sign appeared in heaven: behold, a great, fiery red dragon having seven heads and ten horns, and seven diadems on his heads. His tail drew a third of the stars of heaven and threw them to the earth" (Revelation 12:3-4; angels are called stars in Revelation 1:20).
2. Demons help Satan in deceiving people with false teachings.
"Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons" (1 Timothy 4:1).
3. To defeat these enemies of God, we need the armor of God.
"Put on the whole armor of God, that you may be able to stand against the wiles of the devil. For we do not wrestle against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places" (Ephesians 6:11-12; see verses 13 to 20 for the full listing of the armor).
For more about using the armor of God to defend ourselves from these spiritual forces, see the Free Bible Study Guides series on The Armor of God.