"This Church Jesus commissioned is historically and unarguably the Catholic Church, and it still speaks today with the same authority and protection from error by the Holy Spirit that Jesus gave it from the beginning."
What a load of shite.
"I declare X to be true and further declare that you cannot argue with X or question X. Further, it is a sin to even so much as think about questioning X."
Doesn't quite work, does it? Oh, I know: Not me, "God declared it!" That's better. You gonna question God?? Who are you to question God?!?
The whole basis of the Catholic Church is a series of dogmas that are just flatly asserted to be true without any evidence. Period. No questioning is allowed.