Weirdly - we have to go to Deuteronomy's 'Shema' - the prayer of devotion to God - to understand the mark of the beast.
Deuteronomy 6:4-8 "Hear, O Israel: The Lord our God, the Lord is one. Love the Lord your God with all your heart and with all your soul and with all your strength. These commandments that I give you today are to be on your hearts. Impress them on your children. Talk about them when you sit at home and when you walk along the road, when you lie down and when you get up. Tie them as symbols on your hands and bind them on your foreheads."
Then when we come to Revelation 13, we have Military power represented in the first beast and the propaganda machine for Economic power in the second beast.
Now, what's with the 666? First, the Hebrew number symbolism is significant, in that 6 is the number of a man. It's the number of the day we were created on, the days of the week we work, and short of God's perfect 7.
There's also another potential twist - the gematria (taking Hebrew letters as numbers) for both "BEAST" and / or "Nero Caesar" apparently both equal 666 when added up from the Hebrew.
In other words, don't bind your politics and materialism to your hands and forehead. Don't worship your leader or money. Stay true to Christ - no matter what happens. Jesus is worth it. Instead - be one of those in the very next Chapter that have their Father's name written on their foreheads!
This video explains more - 11 minutes for the second half of Revelation - well worth it. Share at church! 2.1 million views so far