I believe I have already answered that question.
If we abide by the most basic of well-established and long-held principles of sound exegesis then we know we have to start with how the original author and his original readers would have understood what was written. We know we can't impose 17th, 21st, or 49th century conditions on the text because the original audience knew nothing of those things. God is omniscient so He knows everything, but the book was written to
first century Christians and it was written expressly as a revelation revealing to them things that had happened, things that were happening, and things that would come afterwards..... in a way
they would understand. In order for chips, cell numbers, and DNA to be true we'd all have to ignore the audience affiliations of the text AND the temporal qualifiers. If we continue to abide by basic exegesis principles then the first place to look to understand the meaning of anything not made clear is first and foremost scripture itself, not 15th, 20th, or 33rd century technology. That is why I suggested starting with Deuteronomy 6 where we read an early mention of hand and forehead.
That is something the first century reader would have understood (especially since John is the most Jewish of the NT authors). The content of the Dt. 6 text becomes a theme that runs through the entirety of scripture so I question why it would be ignored by anyone.
Even if we were to put aside the concept of scripture rendering scripture, of scripture being its own best source for understanding itself, we'd still have the concept or original meaning and original understand with which to understand Rev. 13's "mark." That means if the "mark" is not something place on hand or head, then the mark might be a scar, or a tattoo, or burn or something known to exist in the first century. For example, in most of the surrounding cultures the punishment for certain crimes was a scar. Adulterers, for example would have their face lacerated so the resulting scar would tell everyone the person was an adulterer. Thieves would have a hand removed. If any of these are the "mark" then there is, again, important scriptural significance to this because Tanakh prohibited maiming, scarification, and tattooing. If the mark is not a reference to something in the Christian scriptures already known to the original audience, then it is a
pagan practice already known to exist by the original readers.
A lot of people believe Revelation (and some of the other apocalyptic content in other books) refers to Rome but
without digressing far afield of this op, I'd like to suggest Jerusalem is the more likely city in question, not Rome. I do not mean to necessarily exclude Rome because both cities can be spoken of, not just one or the other. Jerusalem, like Rome was a city built on seven hills. Jerusalem is where the Law with which Christians concerned themselves was practiced, not Rome (so the reference to the "lawless man" begs the question, "Which law? The Law of God or the law of Caesar?" and "Why would Paul be telling Christian readers to watch for someone who disobeyed Roman law?" Every Christian living in the NT era disobeyed Caesar by believing Jesus, not Caesar, was King of all Kings and God incarnate! So..... look first to scripture to answer the question, "
What is the 'mark'?"
Whether in the past or in the future, the mark must be something that would have been understood by the original audience.
So don't believe Christian teachers who speculate using modern conditions unknown to the original readers because they've left scripture and are imposing on the text things unknown to the original readers.
