But every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world. - 1 John 4:3
"For in the last days false prophets and corrupters shall be multiplied, and sheep shall be turned into wolves and then shall the deceiver of the world appear, pretending to be the Son of God, and [he] shall do signs and wonders, and the earth shall be delivered into his hands” - Didache A.D. 70. This startling saying from early Church writings shows the acceptance and not denial that a future false Christ will appear and deceive many in the world. Our Lord's first words to his disciples about the end of age were: "Watch out that no one deceives you. For many will come in my name, claiming, ‘I am the Messiah,’ and will deceive many." (Matthew 24:4-5). As believers in the Lord we need to be on guard against such deceivers in our day who come in the name of Christ and even do many wonderful miracles and signs but do not carry with them the testimony of the cross. As Polycarp in Smyrna said, "Whoever does not confess the testimony of the cross is of the devil." We must not only look at the outward show of power but what is their message being given. Is the faith once given to the saints being proclaimed, the Apostles Creed and other fundamental beliefs upheld, or is there a show in the flesh of power and new doctrines that tickle the ears and sound good.
There is an old large painting in a Church done in the 14th century called: "Fresco of the Deeds of the Antichrist." In this picture you see crowds of people, religious men, and a church building in the background. The keynote element of the painting is a christ-like figure standing on a raised pulpit and at first glance it appears as if he is Christ Himself. Though at closer inspection you realize this is a pseudo-Christ or Anti-Christ, one in replacement of the true Son of God. And then the pictures details become horrific as you notice crowds of people mesmerized and enchanted by this false Christ and other scenes of showing how satan fell as lightning from heaven and how men were filled with demons and the deceivers were in the earth doing their work. It shall come in the same way, in the last of days the devil will come as an angel of light and deceive many people. Whether we will see the actual anti-Christ or not is not the issue but are we on-guard against this deception that will grow greater and greater until that last day. As our Lord warned us let us "watch out" and be on guard.