Just throwing this out there.
The Body of Messiah is the entirety of all believers being built up into a holy temple (Ephesians 2:20-22). For hundreds of years the Popes sat as the self proclaimed "vicars of God" ruling over believers worldwide (sitting in the temple of God). Here are a few quotes to consider in this regard;
"The Pope and God are the same, so he has all power in Heaven and earth."
Pope Pius V, quoted in Barclay, Chapter XXVII, p. 218, “Cities Petrus Bertanous”
“The Pope takes the place of Jesus Christ on earth…by divine right the Pope has supreme and full power in faith, in morals over each and every pastor and his flock. He is the true vicar, the head of the entire church, the father and teacher of all Christians. He is the infallible ruler, the founder of dogmas, the author of and the judge of councils; the universal ruler of truth, the arbiter of the world, the supreme judge of heaven and earth, the judge of all, being judged by no one, God himself on earth.” the New York Catechism.
“To believe that our Lord God the Pope has not the power to decree as he is decreed, is to be deemed heretical.” the Roman Canon Law 1685
Pope Nicholas I declared: "the appellation of God had been confirmed by Constantine on the Pope, who, being God, cannot be judged by man."
Labb IX Dist.: 96 Can. 7, Satis evidentur, Decret Gratian Primer Para
"The Pope is not only the representative of Jesus Christ, he is Jesus Christ himself, hidden under the veil of flesh." Catholic National, July 1895
"We hold upon this earth the place of God Almighty"
Pope Leo XIII Encyclical Letter of June 20, 1894
In conjunction with those statements, here is John Gill's commentary on verse 3;
a succession of men is here meant, as a king is used sometimes for an order and succession of kings, Deu_17:18 and an high priest for that whole order, from Aaron's time to the dissolution of it, Heb_9:7 so here it intends the whole hierarchy of Rome, monks, friars, priests, bishops, archbishops, cardinals, and especially popes, who may well be called "the man of sin", because notoriously sinful; not only sinners, but sin itself, a sink of sin, monsters of iniquity, spiritual wickednesses in high places: it is not easy to reckon up their impieties, their adulteries, incest, sodomy, rapine, murder, avarice, simony, perjury, lying, necromancy, familiarity with the devil, idolatry, witchcraft, and what not? and not only have they been guilty of the most notorious crimes themselves, but have been the patrons and encouragers of others in sin; by dispensing with the laws of God and man, by making sins to be venial, by granting indulgences and pardon for the worst of crimes, by licensing brothel houses, and countenancing all manner of wickedness;
Here is Gill's commentary on verse 4;
Who opposeth,.... Or is an opposer, an adversary of Christ, the antichrist; who opposes him in his kingly office, styling himself the head and spouse of the church, assuming to himself all power in heaven and in earth, taking upon him to dispense with the laws of Christ, and to make new ones; who opposes him in his priestly office, by pretending to offer him up again in the sacrifice of the mass, and by making angels and saints departed, intercessors and advocates; and also in his prophetic office, by teaching for doctrines the commandments of men, and setting up unwritten traditions before the word of God, requiring the worshipping of images, angels, and saints, when Christ requires that the Lord God only should be worshipped and served; and by introducing the doctrine of works and of merit instead of grace, and with a multitude of other things, in which he most manifestly appears to be diametrically opposite and contrary to Christ:
I highly suggest you read the rest of Gill's commentary on verse 4. I will post it all if someone does not have access to Gill's commentary.