Revelation 13:11-18 has caused much speculation over the years.
11 Then I saw another beast rising out of the earth. It had two horns like a lamb and it spoke like a dragon. 12 It exercises all the authority of the first beast in its presence, and makes the earth and its inhabitants worship the first beast, whose mortal wound was healed. 13 It performs great signs, even making fire come down from heaven to earth in front of people, 14 and by the signs that it is allowed to work in the presence of the beast it deceives those who dwell on earth, telling them to make an image for the beast that was wounded by the sword and yet lived. 15 And it was allowed to give breath to the image of the beast, so that the image of the beast might even speak and might cause those who would not worship the image of the beast to be slain. 16 Also it causes all, both small and great, both rich and poor, both free and slave, to be marked on the right hand or the forehead, 17 so that no one can buy or sell unless he has the mark, that is, the name of the beast or the number of its name. 18 This calls for wisdom: let the one who has understanding calculate the number of the beast, for it is the number of a man, and his number is 666.
I think William Hendriksen gives by far the best explanation in his outstanding commentary on the book of Revelation, More Than Conquerors.
Here is an extended quote:
“The two beasts (cf. v1 & 11) —anti-Christian government and anti-Christian religion—work in perfect cooperation. That is invariably the case. It was already true in the days of the apostle…Heathen religion and heathen politics cooperated with one another in their battle against the Church.
Now, to all—small and great, rich and poor, free and bond—the false prophet gives a mark. It is the mark of the first beast. Here the false prophet, in outward appearance, resembles the Lamb. Have not the followers of the Lamb been sealed on their foreheads? Hence the followers of the beast must be marked or branded on their foreheads or right hands.
But what is meant by this “mark of the beast”?
Various amusing answers have been given. These theories err in this respect, namely, that they interpret this mark as a single, individual, outward, visible sign that will appear on the forehead or hand of the wicked at one particular moment in history; then, and then only. But the beast always persecutes the Church and indicates every form of secular power that tries to destroy believers. Wherever and whenever the beast appears, you will also find the mark of the beast. The two go together and cannot be separated.
In order to understand the expression “mark of the beast” we must remember that not only cattle but slaves also were branded or marked. The mark meant that the slave belonged to his master. Very soon the expression “to receive the mark of someone” began to mean to belong to someone, to serve or worship someone.
So “receiving the mark of the beast” seems to mean “belonging to the beast and worshiping the beast.”
The “mark of the beast” is the God-opposing, Christ-rejecting, Church-persecuting spirit of Antichrist, wherever and whenever it shows itself. This mark is impressed on the forehead or right hand (cf. Deut. 6:8). The forehead symbolizes the mind, the thought life, the philosophy of a person. The right hand indicates his deed, action, trade, industry, etc.
Therefore, receiving the mark of the beast on the forehead or right hand indicates that the person so characterized belongs to the company of those who persecute the Church; and that—either preeminently in what he thinks, says, writes, or more emphatically in what he does—this anti-Christian spirit becomes evident.
This interpretation harmonizes entirely with our explanation regarding the seal that the believer receives on his forehead. This seal indicates that he belongs to Christ, worships Him, breathes His spirit, and thinks His thoughts after Him.
Similarly, the mark of the beast symbolizes that the unbeliever, who persists in his wickedness, belongs to the beast and therefore to Satan, whom he worships.
Observe, however, that there is a difference. The believer receives a seal, the unbeliever a mere mark.
Throughout the dispensation it has been true that those people who have not received the mark of the beast and have not worshiped his image have been thwarted in their business pursuits. They are the ones who are crowded out and oppressed. They are not allowed to buy or to sell as long as they remain loyal to their principles. As we approach the end this opposition will increase.
Nevertheless, let not the believer despair.
Let him remember that the number of the beast is the number of man. Now, man was created on the sixth day. Six, moreover, is not seven and never reaches seven. It always fails to attain to perfection; that is, it never becomes seven. Six means missing the mark, or failure. Seven means perfection or victory. Rejoice, O Church of God! The victory is on your side. The number of the beast is 666, that is, failure upon failure upon failure! It is the number of man, for the beast glories in man, and must fail!” (Hendriksen p. 149-151)
What a helpful explanation.
Deuteronomy 6:8 & 11:18 also commend the above explanation.
“You shall bind them (the commandments) as a sign on your hand, and they shall be as frontlets between your eyes.” (Deuteronomy 6:8)
Many orthodox Jews take these verses very literally and tie small leather boxes on their heads and arms. These tefillin or phylacteries contain scrolls of parchment inscribed with verses from the Torah.
However, these verses should probably not be understood literally, but figuratively: Moses commending the people of Israel to be thinking (foreheads) and doing (hands) the commandments.
God’s people were to fill their minds with God’s word so that they could obey God’s Word and do God’s Word.
The same should be true of Christian people today: saturate our minds with the Bible so we can do what it says. Fill our minds with gospel truth so that we can live in such a way that pleases God.
The mark of the beast is the exact opposite. It is indicative of people whose minds (foreheads) are saturated with worldly, non-Christian, secular philosophies and they therefore act (hands) in accordance.
Many people today have the mark of the beast and don’t know it.
It’s not the vaccine. Nor a microchip. But someone rejecting Jesus.