Revelation: The Mark of God - What is the \"mark\"? Is it easily identified or an unsolved mystery?

the forehead:

... he placed his right hand on me and said: Do not be afraid. I am the First and the Last. Revelation 1:17




the right hand:

7And He came and took the book out of the right hand of Him who sat on the throne. Rev 5

Then the voice that I had heard from heaven spoke to me once more: \"Go, take the scroll that lies open in the hand of the angel who is standing on the sea and on the land. Revelation 10:8

...there before me was the Lamb, standing on Mount Zion, and with him 144,000 who had his name and his Father\'s name written on their foreheads. Revelation 14:1

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