A question was turned in for our Ask Anything series that simply stated, "What's the mark of the beast in Revelation 13 and 14?" While this topic has been debated (often badly) for centuries, I think we can make a few observations that are helpful.
First, it is useful to know more about the book of Revelation. As odd and foreign as some of the language sounds to our modern ears, this type of literature was quite common in the early centuries. It was a genre known as "apocalyptic" literature. This type of writing was known by its high use of imagery and symbolism. Often, apocalyptic literature was used as a method for criticizing the powers-that-be without directly using their names. Another feature of this genre is its "already/not yet" use of language. This simply means that apocalyptic literature had a dual purpose: it addressed a current situation, but also pointed forward to a coming time when similar events would occur or prophecies would be fulfilled.
This basic understanding of Revelation is useful because it helps us see that the author, John, was writing about a very real beast (Rome) in his day. And while we do believe that the words of Revelation give us great insight into what might be in the future (the "not yet"), Revelation is best understood in the context of 1st century Rome. The Mark of the Beast at that time was very likely (although this could be disputed) association with what was called "the emperor's cult". The emperor of Rome at that time would literally set himself up as a god and expect to be worshiped. Those who did could be said, in a sense, to be "marked" for the emperor and they enjoyed great freedom in the Roman empire. This is why Christians (and Jews for that matter) had so much trouble in that era- their system of belief put them in direct opposition to the ruling religion, which often resulted in persecution and even death.
A second helpful observation is the meaning and purpose of the mark. In Revelation 13, it is quite clear that the mark of the beast would set someone apart as having chosen to follow the beast and his rule. What this means for us is that the mark of the beast, should something like this occur in our lifetime, is not something you can get by accident. From time to time, I hear people warn about different products or technological innovations as being a potential mark of the beast. Don't buy that for a second. Using a credit card is not the sign of the beast. Owning an ipod is not the sign of the beast. Even if they begin inserting electronic chips into our hands as a way of doing banking faster, this will not be the sign of the beast! How can I make such a claim? Because Revelation 13 so clearly associates the mark with the beast himself- those who chose his mark knew clearly what they were doing. No one was tricked into being marked. Should we ever see a current "mark of the beast", it will be a clear decision to reject God and embrace a different rule in our life. Until I see that choice being forced, I won't worry about it!
So, what is the mark of the beast? I have no idea. But I do know that in Revelation 14, there is a whole different group of peope who don't have the mark of the beast. Rather than having the name of the beast on their forehead, they carry the name of the Father. They have set themselves apart for Him. As we watch our culture and wonder if the end times are near, this is the best thing we can do- to be "marked" by our love and devotion to the Father. If we continually bear this mark, we have no reason to fear the mark of the beast.