Since the Fall, the cosmic war has been going. Satan and his minions deceive and oppose God’s people, but they triumph through His truth and power.
The prince of the kingdom of Persia withstood me twenty-one days, but Michael, one of the chief princes, came to help me, for I was left there with the kings of Persia, and came to make you understand what is to happen to your people in the latter days. For the vision is for days yet to come. Daniel 10:13-14
For many deceivers have gone out into the world, those who do not confess the coming of Jesus Christ in the flesh. Such a one is the deceiver and the antichrist.
Second John 1:7
Daniel was in a time of deep mourning for three weeks. He fasted and prayed. God sent an angel to him, but, at first, he was more frightened than strengthened. The angel addressed him kindly and called him a man greatly loved. Daniel’s prayers had been heard from the first day of that three-week period, but the angel had been opposed by the prince of the kingdom of Persia.
John, in this second epistle, warns his readers about the deceivers in the world. They are identified as those who do not confess the coming of Jesus Christ in the flesh. The Reformation Study Bible  notes explain that a heresy called Docetism taught that Jesus did not have a real human body but was some sort of phantom who only appeared to be human. John declared these false teachers to be of the Antichrist.
Think about it
Once again in these passages, we see the very real nature of the spiritual war going on around us. Satan and his forces wield a certain amount of power, but God does hear His children when they pray. He does send aid. He will judge all the hosts of wickedness and deliver His own safely to glory (Isaiah 24:21; Ephesians 6:11-12; Second Peter 2:4; Revelation 17:8; 20:10).
There’s a war on, but God has all things under His control. Trust Him and obey His truth. As we saw yesterday, His children will be victorious over the world through Jesus Christ.
 The Reformation Study Bible, Sanford, FL, Reformation Trust, 2015, p. 2279