And the great dragon was thrown down, that ancient serpent, who is called the devil and Satan, the deceiver of the whole world—he was thrown down to the earth, and his angels were thrown down with him.
In the dramatic vision from John the apostle recorded here, we get a reminder of what the devil does. The devil is the deceiver of mankind from the ancient days of the fall of Adam and Eve in Eden, all the way to these present days. He accuses God's people as Satan and he deceives all the world. He is a liar, an attacker, and a deceptive tempter for individuals and nations to do great evil. In John's vision it takes all the warrior angels of heaven's host led by Michael himself to cast Satan and his demons down to earth.
Make no mistake about it, the battle over sin and the devil's work is deeply spiritual and really hard! Sin came into the world as the devil's design to mar God's perfect work, and even though Jesus has defeated sin and death, Satan still fights frenetically fierce for his pride. God's angels can defeat him as Christ has, but we must appeal to the power of Christ. Our flesh will fall to him if we don't. Even in this context, the devil emboldens the world against the rule of Christ, and Christians are killed indiscriminately in his hatred. This looks to the entire earth like evil wins.
Christians have a foe at work in the world today. We don't have to be spooked by the devil though, because the Holy Spirit of God resides within us and greater is He that is in us than He that is in the world! Yet we should not take any battle with sin lightly. That would be a great deception. The devil is still very much a master of deception and he will get the upper hand on us if we aren't careful, which is why we are warned to watch our doctrine and practice closely.
This is why we need to stand strong, praying in the Spirit and strengthening our hands and hearts in the Word of God. The devil runs from the Word of God and if we stay strong, refusing to let him twist the truth of scripture, we will not be deceived by him. We may be attacked. Some may even be killed, but God keeps our souls safe.