The following is an excerpt from The MacArthur New Testament Commentary on Revelation 13.

And he causes all, the small and the great, and the rich and the poor, and the free men and the slaves, to be given a mark on their right hand or on their forehead, and he provides that no one will be able to buy or to sell, except the one who has the mark, either the name of the beast or the number of his name. (Revelation 13:16–17) 

As part of his plan to enforce the worship of Antichrist, the false prophet will require all categories of unbelievers, summarized as the small and the great, and the rich and the poor, and the free men and the slaves, to be given a mark on their right hand or on their forehead. Mark (charagma; from charasso, "I engrave") was the term for images or names of the emperor on Roman coins. In the ancient world, such marks (tattoos or brands) were commonly given to slaves, soldiers, and devotees of religious cults (cf. Gal. 6:17). God sealed, with a mark on the forehead, the 144,000 to preserve them from His wrath against the unbelieving world (7:2–3); the false prophet marks the unsaved to preserve them from Antichrist’s wrath against God’s people. The mark will signify that the person bearing it is a worshiper and loyal follower of the Antichrist. In much the same way, the Roman emperors required their subjects to prove their loyalty by offering sacrifices to Caesar. Those who refused, like those who refuse to take the Antichrist’s mark, were subject to execution.

Besides the constant threat of death, refusing to take the mark of the beast will have dire practical consequences in daily living: no one will be able to buy or to sell, except the one who has the mark. Antichrist’s empire will maintain strict economic control over the world. Food, clothing, medical supplies, and the other necessities of life potentially in demand in the devastated earth, which has felt the judgment of God (6:5–6), will be unobtainable for those without the mark. Currency will probably vanish, to be replaced by controlled credit. Instead of a credit card, which can be lost, people will have a mark (possibly a bar code) in their forehead or hand. Scanning people’s foreheads or hands would identify them to a central computer system. Life under totalitarian governments in our time provides a faint glimpse of what is to come. A man who had lived under Bulgaria’s communist regime remarked:

You cannot understand and you cannot know that the most terrible instrument of persecution ever devised is an innocent ration card. You cannot buy and you cannot sell except according to that little, innocent card. If they please, you can be starved to death, and if they please, you can be dispossessed of everything you have; for you cannot trade, and you cannot buy and you cannot sell, without permission. (Cited in W. A. Criswell, Expository Sermons on Revelation, 4:120–21)

The pressure to give in to the worship of Antichrist will be far worse than anything ever experienced in human history. Life will be virtually unlivable, so the people are forced to bow to the demonized king, not prompted merely by religious deception, but also by economic necessity.

Further describing the mark, John notes that it will consist of either the name of the beast or the number of his name. Antichrist will have a universal designation, his name within a numbering system. The exact identification of that phrase is unclear. What is clear is that everyone will be required to have the identifying mark or suffer the consequences.