The "Foreheads"

""The two opposing marks are to be received in the forehead, which is a symbol of the mind and affections, since the forehead is the seat of the intellectual faculties.

--The seal of God can be received nowhere else. He accepts of no obedience but that which is from the heart.
--But the beast seems to be more accommodating. If you do not choose his mark in the forehead, you may receive it in your right hand.
If you do not believe and love his institutions, you may obey them outwardly - carry out his requirements with your right hand, which is a symbol of outward actions. 

The Devil does not care for sincerity of heart in his service.

Those who receive the seal of God, have the Lamb's "Father's name written in their foreheads" Revelation 14:1.
Those who receive the mark of the beast, receive the "mark of his name." Verse11.
Name is used in a figurative sense to denote authority.
In the name of the people, in the name of the king, signify by the authority of the people, or of the king.

In the name of Jesus Christ, means by the authority of Jesus Christ.

---Hence, the mark of the beast is a sign or token of his authority, standing in opposition to the sign of the authority of the Father."
RFC