The Bible teaches that demons are fallen angels who, having rebelled against God, actively oppose His kingdom and seek to harm humanity. While they possess real, malevolent power, they are ultimately subject to the sovereign authority of Jesus Christ, who came to destroy the works of the devil.
The Scriptures and the Reformed confessions maintain that demons were originally created as good angels but fell from their excellency by their own free will. As noted in the Belgic Confession Art. 12, these evil spirits are 'so depraved, that they are enemies of God and every good thing,' acting as murderers who seek to ruin the Church. The Second Helvetic Confession Ch. VII reinforces this, citing Christ's own testimony that the devil 'was a murderer from the beginning' and 'the father of lies.' They are not independent powers of evil equal to God, but creatures who, through their own rebellion, expect eternal judgment.
The Gospels provide vivid accounts of Jesus' absolute authority over the demonic realm. In the account of the Gerasene demoniac, the unclean spirits immediately recognize Jesus as the 'Son of the Most High God' and are powerless to resist His command (Mark 5:7; Luke 8:28). They are compelled to ask for permission even to enter a herd of swine, demonstrating that they operate only under the sovereign sufferance of Christ. While they may cause immense suffering and chaos, the Gospel is the good news that the 'Beloved Son of the Father' has come to break their power and deliver those held captive by the enemy.
It is essential for the believer to remain vigilant against 'seducing spirits and doctrines of demons,' as warned in 1 Timothy 4:1. However, our response is not one of fear, but of faith in the finished work of Christ. As Athanasius articulated in On the Incarnation Section 52, the disciples of Christ do not war against flesh and blood but stand arrayed against the devil through virtuous action, self-restraint, and prayer. We are called to be sober-minded, knowing that while the enemy prowls, we are 'accepted and loved in Christ'—a position that no demon can ever steal from the elect.