AntiChrist, sitting in the Temple...

Calvin's Institutes (1559)
Book 4 of 4 - External Means by which God Invites Us into the Society of Christ and Holds Us Therein

Chapter 2 - Comparing the false and true church

7-11 - Rome resembles Israel under Jeroboam

7. They had the truth, but fell from it to corruption.

8. There was a trace of the church left, as they fell away in degrees.

9. Rome is WORSE than Israel under Jeroboam, for Israel's sacrifices themselves were not corrupt. Thus, the prophets did not and didn't need to separate and set up separate pure worship. But Rome's worship is inherently idolatrous in their Mass. And they demand we participate in it, and honor Rome as much as Christ does His church. "The communion of the church ought not to extend so far that, if it degenerates into profane and corrupted rites, they have to follow it headlong."

10. There were times when the prophets declared Israel's assemblies profane (Isa 1:14), and "had to depart from agreement with those assemblies." If Rome is a true church, we must submit to their legit power of the keys. But they are disowning genuine believers!

11. Like a building demolished, Rome is still a church, with a recognizable foundation and ruins. "Their treachery could not obliterate His faithfulness, and circumcision could not be so profaned by their unclean hands as to cease to be the true sign and sacrament of His covenant." God still counted Israel His children, in the midst of their deepest idolatry - Ezek 16:20-21. The main thing still standing is "baptism," which "retains its force despite the impiety of men."

12. But this doesn't make Rome the one true church. Doctrine is also important to the "true and lawful constitution of the church," which this argument is really about. The pope is the antichrist, sitting in the church - Dan 9:27; 2 Thess 2:4 - where "Christ lies hidden, half buried, the gospel overthrown, piety scattered, the worship of God nearly wiped out. Rome has "churches to the extent that the Lord... preserves in them a remnant of His people." But they "lack the lawful form of the church," as their doctrine confounds the gospel.