Revelation 14:9-10 ASV
(9) And another angel, a third, followed them, saying with a great voice, If any man worshippeth the beast and his image, and receiveth a mark on his forehead, or upon his hand,
(10) he also shall drink of the wine of the wrath of God, which is prepared unmixed in the cup of his anger; and he shall be tormented with fire and brimstone in the presence of the holy angels, and in the presence of the Lamb:

What is the TRUE Message of the third Angel when Jesus has revealed the Godhead to whomever?

There is the mark (sphragis, σφραγις) or seal of God on our foreheads to welcome and there is the mark or seal (charagma, χαραγμα) of the beast to avoid in the Apocalypse.

The Greek word which is used to refer to the 'mark of the beast' is the same word which Paul used in Acts 17:29 to forbid idolatry, allegiance to 'sculpture or mark' of art, alongside gold, silver, and stone sculpture, because we are also gods of the race of God. Acts 17:29.

Revelation 7:3 ASV
(3) saying, Hurt not the earth, neither the sea, nor the trees, till we shall have sealed the servants of our God on their foreheads.

Revelation 9:4 ASV
(4) And it was said unto them that they should not hurt the grass of the earth, neither any green thing, neither any tree, but only such men as have not the seal [mark] of God on their foreheads.

Acts 17:27-30 ASV
(27)  that they should seek God, if haply they might feel after him and find him, though he is not far from each one of us: (28)  for in him we live, and move, and have our being; as certain even of your own poets have said, For we are also his offspring. (29)  Being then the offspring of God, we ought not to think that the Godhead is like unto gold, or silver, or stone, graven by art and device of man. (30)  The times of ignorance therefore God overlooked; but now he commandeth men that they should all everywhere repent:

Romans 4:9-12 ASV
(9) Is this blessing then pronounced upon the circumcision, or upon the uncircumcision also? for we say, To Abraham his faith was reckoned for righteousness.  (10)  How then was it reckoned? when he was in circumcision, or in uncircumcision? Not in circumcision, but in uncircumcision:  (11)  and he received the sign [another word meaning also MARK] of circumcision, a seal [MARK] of the righteousness of the faith which he had while he was in uncircumcision: that he might be the father of all them that believe, though they be in uncircumcision, that righteousness might be reckoned unto them;  (12)  and the father of circumcision to them who not only are of the circumcision, but who also walk in the steps of that faith of our father Abraham which he had in uncircumcision.

1 Corinthians 9:2 ASV
(2)  If to others I am not an apostle, yet at least I am to you; for the seal [MARK] of mine apostleship are ye in the Lord.

2 Timothy 2:19 ASV
(19)  Howbeit the firm foundation of God standeth, having this seal [MARK], The Lord knoweth them that are his: and, Let every one that nameth the name of the Lord depart from unrighteousness.

Revelation 6:9 ASV
(9)  And when he opened the fifth seal, I saw underneath the altar the souls of them that had been slain for the word of God, and for the testimony which they held:

Revelation 22:10 ASV
(10)  And he saith unto me, Seal not up the words of the prophecy of this book; for the time is at hand.

If we understand the nature of the mark of Jesus (God) we can understand what the mark of the beast is (Revelation 14:9).

Paul speaks of the actual 'sign' or the actual 'act' of the circumcision of Abraham as a symbolic 'MARK of the righteousness of the faith which he had' (Romans 4:9-12 ASV). Paul speaks to the Corinthians of the symbolic 'MARK' of his Apostleship in the fact that they are in Jesus [Jehovah] (1 Corinthians 9:2 ASV). Paul speaks to Timothy of the symbolic seal [MARK] which is 'that Jehovah | Jesus knew the ones who are of Him and that the ones calling the name of Jehovah | Jesus must turn from adikia, which is injustice, abuse, unrighteousness' (2 Timothy 2:19). 

The mark of the beast must be contrary to the mark of God | Jesus: ungodliness, unrighteousness, injustice, the belief in a doctrine of men that is contrary to the belief (faith) of Jesus | God or to the foundation of God (2 Timothy 2:19), witnessing against or echoing against the commandments or the word of God (Revelation 14:12), against His witnessing (Acts 1:8), seeking worship from the saints (Matthew 4:10), and distorting the belief of Jesus.

John the Baptist speaks of the seal [MARK] that God is true:

John 3:31-36 ASV
(31)  He that cometh from above is above all: he that is of the earth is of the earth, and of the earth he speaketh: he that cometh from heaven is above all.
(32)  What he hath seen and heard, of that he beareth witness; and no man receiveth his witness.
(33)  He that hath received his witness hath set his seal [MARK] to this, that God is true.
(34)  For he whom God hath sent speaketh the words of God: for he giveth not the Spirit by measure.
(35)  The Father loveth the Son, and hath given all things into his hand.
(36)  He that believeth on the Son hath eternal life; but he that obeyeth not the Son shall not see life, but the wrath of God abideth on him.

The same Greek work that John the Baptist and Paul used to speak of sealing or marking is the same word that Apostle John used in the Apocalypse for the sealing or marking on the foreheads of the ones who are of Jesus (Revelation 7:3; 9:4).

The mark (sphragis, σφραγις) of Jesus | God contrasts with the idolatrous mark, emblem, sculpture (charagma, χαραγμα) of the beast.

What is the religion of Jesus? It is the religion of Christian Judaism. Sphragis! The acolytes of Jesus obey the voice of Jesus in Moses and the Prophets and in the New Testament, love one another, and witness Jesus to be YEHOSHUA MESSIAH YHWH and that He was risen on a Saturday, the first of the seven sabbaths leading to Pentecostal day.

What is the religion of the beast? It is the religion of Babylon. Charagma! Babylon is the religion of men who decree religious observances for God and teach against the words of Jesus by adding, subtracting, going to the left or to the right (interpreting) of His words which had been closed long ago in the desert before the conquest of Canaan.

Is the mark of the beast currently being received? At the last cry, in the last days, when every living soul is given as prey to the beast for man to choose to worship Jesus or the beast and his image, the marking will be more palpable. 

Those of my generation tasted a preview of what a universal mandate entails in the years of COVID-19.

2 Corinthians 11:13-15 ASV
(13)  For such men are false apostles, deceitful workers, fashioning themselves into apostles of Christ. (14)  And no marvel; for even Satan fashioneth himself into an angel of light. (15)  It is no great thing therefore if his ministers also fashion themselves as ministers of righteousness, whose end shall be according to their works.

Genesis 9:3-4 ASV
(3)  Every moving thing that liveth shall be food for you; as the green herb have I given you all. (4)  But flesh with the life thereof, which is the blood thereof, shall ye not eat.

Note: God (MESSIAH YAHWEH YEHOSHUA) commands to eat flesh not with the blood and the fat but SDA teaches not to eat flesh, et cetera. Who contradicts Jesus? SDA teaches Jesus is Archangel Michael (John 8:24). It only takes one sin or iniquity (Ezekiel 33:13.).