According to reformed theology, in the Savoy Declaration of Faith, Chapter 26 (Of the Church), paragraph 4, the Pope is the Antichrist.
There is no other Head of the Church but the Lord Jesus Christ; nor can the Pope of Rome in any sense be head thereof; but is that antichrist, that man of sin, and son of perdition, that exalteth himself in the Church against Christ, and all that is called God, whom the Lord shall destroy with the brightness of his coming.
Also in the 1689 Baptist Confession of Faith, Chapter 26 (Of the Church), paragraph 4, we found the same, the Pope as the Antichrist.
The Lord Jesus Christ is the Head of the church, in whom, by the appointment of the Father, all power for the calling, institution, order or government of the church, is invested in a supreme and sovereign manner; neither can the Pope of Rome in any sense be head thereof, but is that antichrist, that man of sin, and son of perdition, that exalts himself in the church against Christ, and all that is called God; whom the Lord shall destroy with the brightness of his coming.
But how can he be THE Antichrist, as 2 Thessalonians 2: 2-9 says, if it is talking about a position and not a person. Would not be more in line with the concept of the spirit of the antichrist, of which it is spoken of in 1 John 2: 18-19 and 1 John 4: 2-3.
How can this paragraph be interpreted? The Pope is an antichrist or the Pope is the Antichrist?