Not everyone believes the mark of the beast on the hand and forehead are literal devices or marks such as computer chips or anything similar, and there are Scriptural reasons to believe they are not... much in the same way we would not accept that just because people were trying to build the tower of Babel meant we think they could have actually reached God that way, through their human means and/or effort, or that the laws written on our hearts are literally etched or chiseled there. The forehead very much represents a person's thinking and beliefs, out of which arise the actions anyone takes and the things we do and what we serve with our hands.
Yes, you're right, Magenta! I think that way too on the subject. Though I have no absolute proof that the scriptures on that subject do not mean an actual visible mark put on people. But it seems very unlikely. For example, think of how hard it would be to afford it in poor countries, such as Africa, especially! If it turns out that anyone asks us to accept a mark - I think it important not to take it, just in case. But I highly doubt it will happen. I think it is much more likely speaking in a spiritual sense, regarding "a mark." Those who have been saved and born again, have been sealed by the Spirit. It isn't visible but very real and very important! There are 2 spiritual kingdoms in this world - the devil's and God's. Those who haven't become a child of God belong to the devil's kingdom here on earth. But if they get saved, they then become a part of God's kingdom!
And the difficulty there is predicted to be for Christians in the matter of buying and selling - could simply mean, as numerous times throughout history - that Christians will have greater difficulties economically, during times of persecution. I'm sure it has happened before and would be due to hostility against them.
I've researched with my Bible software, the Bible terms of "left hand, right hand, and forehead" well in the past.
And one passage about a time when invisible numbers were symbolically used to choose people, is this:
Ezek 9:6
6 Slay utterly old and young, both maids, and little children, and women: but come not near any man upon whom is the mark; and begin at my sanctuary. Then they began at the ancient men which were before the house.
KJV