As promised

And I know I will get attacked by all sides - futurists Preterist and whatever other ISTs they are lol
Revelation 13:16 And he causeth all, both small and great, rich and poor, free and bond,
to receive a mark in their right hand, or in their foreheads:
When Revelation 14:! and Revelation 22:4 says all those who believe in Jesus will have the Father's name written in their foreheads it is obviously symbolic - we do not go around with tattoos of the Fathers name or Jesus on our foreheads. Maybe we are all closet Christians worried that people will see

<----sarcasm
So when it comes to Revelation 13:16 "to receive a mark in their right hand, or in their foreheads" It is not a literal mark, it is symbolic. The forehead is the mind of the man, it is where we conceive our doctrine. The hand is the work we do, our actions.
Revelation 13:17 And
that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.
There were many Papal decrees forbidding trading with those who would pledge allegiance to the Pope. For example a cannon of the 3rd Lateran Council, in 1178 AD, under Pope Alexander 111, commanded that no man should entertain or cherish them in his house or land or exercise traffic with them.
The same pope passed a law at the Synod of Tours, that no man should presume to receive or assist the heretics, no not so much as to exercise commerce with them in selling and buying.
Pope Martin V's Bull, at the Council of Constance (1414 to 1418), decreed that "they permit not the heretics to have houses in their districts, or carry on commerce, to enjoy the comforts of humanity with Christians."
By Christians he meant Roman Catholics by the way.
Revelation 13:18 Here is wisdom. Let him that hath understanding count the number of the beast: for
it is the number of a man; and his number is Six hundred threescore and six.
As for the number Six hundred threescore and six (666), LATEINOS (Λατεῖνος) is the Greek word for "the Latin One" and was first suggested by Irenaeus (130 - 202 AD) as the number of the beast.
L – λ – 30
a – α – 1
t – τ – 300
e – ε – 5
i – ι – 10
n – ν – 50
o – ο – 70
s – ς – 200
= 666
In Greek
LATEINOS - Greek for - The Latin One = 666
HE LATINA BASILWIA - Greek for - The Latin Kingdom = 666
ITALIKA EKKLESIA - Greek for - The Latin Church = 666
APOSTATES - Greek for - The Apostacy = 666
In Hebrew:
ROMIITH - The Roman Kingdom = 666
ROMITI - The Roman Man = 666
In Latin:
VICARIUS FILII DEI - Vicar of the Son of God = 666 (VICARIUS FILII DEI is one of the main titles of the Pope)
DUX CLERI - Captain of the Clergy = 666 (the signature of the Pope)
LUDOVICUS - The Vicar of the Court = 666