The Antichrist will sit in the temple of God, tares in the wheat field; with the false prophet performing miracles to deceive those given over to a reprobate mind. A tare is a weed that looks like wheat but does not produce fruit and is used as a symbol of the counterfeit Christian.

Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto Him, that you be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that Day of Christ is at hand.  Let no man deceive you by any means: for that Day shall not come, except there be a falling away first, and that man of sin be revealed, the son of perdition; who opposes and exalts himself above all that is called God, or that is worshipped; so that he, as God, sits in the temple of God, showing himself that he is God.

Howbeit the Most High dwells NOT in temples made with hands; as saith the prophets.  Know ye not that ye are the temple of God, and that the Spirit of God dwells in you?  If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.

The temple is both the Christian as an individual and collectively as the Church.  The mark is a seared conscience (in the Forehead) or an agreement (right hand) with the elements of perdition. Note that the temple is NOT a building to be constructed by the Jews nor is the mark a stamp or tattoo.  These are "red herrings" by which to deceive the very elect, were it possible.

Now the Spirit speaks expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils; speaking lies in hypocrisy; having their conscience seared with a hot iron; having the understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart.

God says "My people are destroyed for lack of knowledge (of God): because you have rejected knowledge, I will also reject thee, that thou shall be no priest to me: seeing how you have forgotten the law of thy God, I will also forget thy children.  I will therefore put you in remembrance, though you once knew this, how that the Lord, having saved the people out of the land of Egypt, afterward destroyed them that believed not."

Do not be unequally yoked together with unbelievers: for what fellowship has righteousness with unrighteousness?  And what communion has light with darkness?  Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you.

For the mystery of iniquity (the Antichrist) does already work: only he (Satan) who now lets will let, until he (Satan) be taken out of the way.  And then shall that wicked (Antichrist) be revealed, whom the Lord shall consume with the Spirit of His mouth, and destroy with the brightness of His coming: even him (the Antichrist), whose coming is after the working of Satan with all power and signs and lying wonders.