Revelation 13:16

13:16 He also caused everyone (small and great, rich and poor, free and slave) to obtain a mark on their right hand or on their forehead.

Revelation 17:5

17:5 On her forehead was written a name, a mystery: “Babylon the Great, the Mother of prostitutes and of the detestable things of the earth.”

Revelation 9:4

9:4 They were told not to damage the grass of the earth, or any green plant or tree, but only those people who did not have the seal of God on their forehead.

Revelation 14:9

14:9 A third angel followed the first two, declaring in a loud voice: “If anyone worships the beast and his image, and takes the mark on his forehead or his hand,

Revelation 20:4

20:4 Then I saw thrones and seated on them were those who had been given authority to judge. I also saw the souls of those who had been beheaded because of the testimony about Jesus and because of the word of God. These had not worshiped the beast or his image and had refused to receive his mark on their forehead or hand. They came to life and reigned with Christ for a thousand years.