“…Even him, whose coming is after the working of Satan with all power and signs and lying wonders, and with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. And for this cause God shall send them strong delusion, that they should believe a lie: that they all might be damned who believed not the truth, but had pleasure in unrighteousness.” 2 Thessalonians 2:9-12 (KJV)
The son of perdition will come in the power of Satan. Remember Satan is only a created being, a creature. He will use signs, and miracles to deceive the nations (Revelation 13:13-14). These “Miracles” will have the influence to deceive only “Those who are perishing”. These are people who will have heard the Gospel of Jesus Christ, but had no use for God, His Spirit, or His Word. They are people who are independent of God, and depend solely on themselves.
Because they refuse to love the truth God will cause them to believe the lie. Even today when someone hears the message of the gospel, and rejects it just one time; his/her heart will grow a little harder toward the gospel. Each time they hear and reject it the chances of their being saved grows weaker. To say again: That is so even in this day of grace.
God can at any point, in the Christ rejecters life, harden that heart. When God hardens the heart it is late, very late for saving grace, and very near to judgment. Do not harden your heart. Believe and receive Jesus as Lord and Savior before it is too late.
This seems – in its context – to apply to those who have rejected “the truth” after the requirement of the “Mark”. Only those receiving the “Mark”, ie. rejecting Jesus Christ as Lord and Savior will receive this “Strong delusion” believing “the lie”.
These are also those who, “Had pleasure in unrighteousness” (See Romans 1:18-32). They worshiped and served the creature [self] rather than the Creator. For the soul to think, “I can wait and be saved following the rapture of the Church.” that is very foolish thinking, and in all probability will not happen. If God is calling you now, and you are rejecting Him now; you will reject Him then as well.