(If I say something that is right, then God has inspired me. If I say something that is wrong, then it is my own mistake.)

The mark of the beast is one of the most discussed subjects in Christian eschatology.
The reason why its a very important issue is because the mark carries eternal consequences. Unfortunately, besides guesswork and speculation, nobody really knows what the “mark” actually is. The only clue that we have is that it has something to do with a number, six hundred and sixty six… which is described as the “number of a man”. There have been many theories attempting to solve the riddle of the “mark” and of these the Mark being a chip implant is the most popular one.

1. The “mark” as a chip-implant.
As of now, the chip implant theory is the most popular theory floating around.
I admit it has its merits, as the possibility of chip implant technology becoming part of a financial system is extremely real. So this theory directly addresses Revelations 13:17.
“no one will be able to buy or to sell, except the one who has the mark”

However, there are certain other problems, both logistical and ethical, with this theory.
A few of them are…

a) It would be impossible for one man or government to ‘chip’ every single human on the planet. Unless of course, the governments of every single country on the map agree to this system.

b) It does not factor in people unaware of Christian teachings on this matter. If the consequences of getting the beasts “chip” is dire, then it would be unfair for these people to be condemned to hell forever.

c) It would be unfair for young children who’s parents decide to have them ‘chipped’.

d) It would be unfair for mentally handicapped people if their caretakers decided to get them chipped.

e) We have uncontacted tribes living in remote rainforests with no electricity. They know nothing of eschatological matters and have no use for a hi-tech chip system. So the idea of them getting chipped and then facing punishment from God is unfair.

f) If the chip is deceptively introduced as part of a new financial program, it would be be unfair to condemn the families that may have opted for the chip only to meet financial requirements.

Basically, it would be unmerciful of God if He were to condemn somebody who takes the anti-christs chip without having enough knowledge of it or if he were unaware of the consequences.

So, what if the mark is something else?

2. Even the believers receive a “mark”
Its well known that the Bible teaches that the beast causes people to receive marks on their foreheads (or their right hands.)

And he causes all, both small and great, rich and poor, free and slave, to receive a mark in their right hand, or in their foreheads:,

But one detail that is left out is that even the followers of God are sealed (marked) in the foreheads, as we see in these verses from Revelations.

“Do not harm the land or the sea or the trees until we put a seal on the foreheads of the servants of our God.”
-Revelations 7:3

They were told not to harm the grass of the earth or any plant or tree, but only those people who did not have the seal of God on their foreheads
-Revelations 9:4.

So we see that people are treated in a certain way depending on the condition of the “forehead”. If a persons forehead did not have the seal of God, then it would have the mark of the anti-Christ and he would face punishment. If the believer has the seal of God, they would be saved. In the end, the condition of our foreheads decides our fate.

3. So, why the forehead in particular? 
This Koranic verse may offer a clue

“Do you see who forbids a servant of Ours (God) when he (turns) to pray? Do you see if he who prays follows the guidance and enjoins righteousness? Do you see if he who obstructs rejects (Truth) and turns away? Does he not know that God sees? Let him beware! If he desists not, We (God) will punish him upon his forehead – a lying, sinful forehead!” 
-Koran 96:9-16

“Punish him upon his forehead”?

The term “forehead” simply represents the frontal lobe regions of our brain. This part of the brain is used to reason and make conscious choices…. including the choice to believe in or reject God.

The executive functions of the frontal lobes involve the ability to recognize future consequences resulting from current actions, to choose between good and bad actions (or better and best), override and suppress socially unacceptable responses, and determine similarities and differences between things or events. wiki

The individual would be making a conscious choice on as to whose side he is going to stand on. We either get the seal of God or the mark of the anti-Christ depending on our choices in this regard. These would be symbolic “seals” or “marks” on the frontal lobe, that people would have brought upon themselves as a result of their choices. Those who consciously reject God will in turn be rejected by God and “punished on the forehead”… by being made a target for the anti-christ. He / She will then receive the anti-christs mark which would identify them as those who are to receive punishment from God.

4. The role of the anti-christ.
The anti-christ or the dajjal is the second beast from the earth as described in Revelations. He would act on behalf or represent the first beast, which is an empire or a regime in the end times and will be the one who would cause the unbelievers to be marked.

The popular teaching is that he would attempt to conquer the world and portray himself as God. But the truth is that God is always in control of the earth, and the anti-christ would only be allowed to rise in order to test the people of the earth. He would essentially serve as an instrument to separate the unbelievers from the believers… who he would cause to be marked.

I could be wrong, but perhaps this verse refers to that very thing.
And when the Word is fulfilled against them (the unjust), we shall produce from the earth a beast to (face) them: He will speak to them, for that mankind did not believe with assurance in Our Signs.
-Koran 27:82

God knows best.