https://schismatic-home-aloner.com/the-mark-of-the-beast-as-an-unlawful-new-form-of-worship-st-thomas/
According to Catholic dogma, a spiritual mark or character is conferred by the sacraments of baptism, confirmation and holy orders. This spiritual mark or character appoints people for divine worship. The “character/mark” is therefore connected to the sacraments and divine worship.
It makes sense that the mark of the beast would be a direct contrast to the mark of Christ and therefore that it would involve a new and false system of worship. By means of these new rites deceived individuals (who wrongly believe they are following the Catholic Church but are actually following apostate antipopes) are appointed to the worship of the beast (by means of the veneration of Antipope John Paul II, the New Mass, etc.). This occurs by way of a massive spiritual deception and a takeover of the temple of God. See: The Temple of God and the Antichrist Located. The beast is pagan Rome under the guise or appearance of the Church, and it occupies the Church’s physical structures. This is why the followers of the beast “wonder” when they see the return of the beast/pagan Rome.
A SPIRITUAL MARK ON THE HAND AND HEAD IN THE OLD TESTAMENT
The teaching of the Old Testament supports the conclusion that the apocalyptic character/mark on the hand or forehead is spiritual rather than physical and that it symbolizes the false worship of the end-times Counter Church. In the Old Testament God commanded people to keep His words and observances as a sign on their hand and forehead. God was referring to a symbolic or spiritual sign on the hand and head, not a physical mark.
In fact, God mentions the spiritual mark on the hand and forehead in connection to observing the Passover.
The Catholic Mass is the new Passover sacrifice that was prefigured by the ancient Passover sacrifice.
So, the mark on the hand or forehead in the Old Testament was a spiritual sign or a symbol representing the proper observance of God’s laws and the sacrifice He instituted. It follows therefore that the apocalyptic mark of the beast on the hand or forehead is a spiritual sign that represents an improper observance of the Mass (the new Passover sacrifice) and a false ecclesiastical structure that deviates from the Lord’s commands and teachings. With regard to the aspect of the mark that deals with buying/selling, we believe that connects to the symbol of the beast (Europa) that is found on the currency of the European Union and the Vatican City State (the political dimension of the beast), as explained in our video Apocalypse Now In The Vatican. The beast has a political and a spiritual dimension. Also note that people are not directly said to be condemned for buying and selling with the mark of the beast but rather for receiving the mark on their hand or in their forehead (the spiritual mark). However, the fact that no one can buy or sell without the mark of the beast also applies, we believe, to the fact that true Catholics who will not submit to the Vatican II Sect and its false worship are denounced as “outsiders”, “schismatics”, “illicit”, and “unapproved”. People literally cannot function within the Vatican II Sect, economically or otherwise, without the mark. True Catholics are ostracized because they won’t receive the mark of the Counter Church, while people like James Martin are fully endorsed.
In our video called Saints & Theologians On The End Times we also showed that St. Thomas connected the end-times with a secession from the spiritual empire of the Romans, that is, with a general defection from the Catholic faith of the Roman Church. Hence, in two different areas St. Thomas’ comments on the end-times were remarkably prescient: 1) By recognizing that the mark of the beast potentially symbolizes a new false form of worship and 2) by asserting that a primary sign of the end-times is a secession from the spiritual empire of the Romans (i.e. a defection from the faith of the Roman Church).
Two other considerations support our conclusion about the mark of the beast. First, the mark of the beast is connected to the veneration of the image of the beast – the veneration of the one who was wounded. The evidence is overwhelming that John Paul II and his false canonization fulfill that prophecy. Since the veneration of the one who is wounded is fulfilled by the Vatican II Sect, it makes sense that the mark on the hand or forehead would be as well. Second, if the mark on the right hand or forehead were a physical mark, that would not deceive basically anyone. But the veneration of the end-times beast is imposed by way of deception. All of these points support the conclusion that the mark of the beast on the right hand or forehead is a spiritual mark that symbolizes the false worship and false authority of the Vatican II Sect, the end-times Counter Church.

The quotes from Exodus are gold. Those tie the language of "the mark" in the Apocalypse specifically to the false "Communion" with the Beast. That is exactly correct and the Old Testament figures prove that is what St. John was referring to.
Two things that are not correct in their analysis.
1. They say that the "buying and selling" in Apocalypse applies in some way to socio-economic buying and selling. That's not correct. The Apocalypse is using the language found in the Parable of the Wise Virgins. The buying and selling allusion in the Apocalypse has the same Sacramental reference. The Gospels speak of our debts being forgiven. This refers to the Sacramental economy of the Church. We get into debt with out sins. We get out of debt by reception of the Sacraments. All of our venial sins are remitted by worthy reception of the Eucharist. The Eucharist looks like a coin. We pay down our sins by taking the Eucharistic coins from the Holy Sacrifice of the Mass.
2. The JPII thing is wrong. In the Dimonds own schema (correct by the way), they count the 7 kings/heads as starting with Pius XI. JPII is the Sixth king/head in their own schema. But Apocalypse 17 describes the Beast/Antichrist in this way:
8 The beast, which thou sawest, was, and is not, and shall come up out of the bottomless pit, and go into destruction: and the inhabitants on the earth (whose names are not written in the book of life from the foundation of the world) shall wonder, seeing the beast that was, and is not. 9 And here is the understanding that hath wisdom. The seven heads are seven mountains, upon which the woman sitteth, and they are seven kings: 10 Five are fallen, one is, and the other is not yet come: and when he is come, he must remain a short time. 11 And the beast which was, and is not: the same also is the eighth, and is of the seven, and goeth into destruction.So this it is clear that the Apocalypse is referring to Bergoglio, who was the eighth head after Pius XI.