It is common for catholic apologists to glorify their church with Bible verses stating the church is superior to scripture. I Timothy 3:15 is one such verse stating the church is the pillar and ground of truth, as if the catholic church was necessary to maintain truth for all time. Notice the verse doesn't say "catholic church" is the pillar of truth. That is assumed by them as if catholic was the only and original body. It wasn't actually.
Notice the church was the pillar in its original form before the ecclesiastical parts of catholicism sprang up, before the papacy or cardinals or metropolitan bishops or the priesthood was separated, before celibacy and such doctrines. The church was the pillar of truth in original form, not in catholic form. Those changes came decades and centuries later. It was the pillar before infant baptism.
The original church is the pillar of truth, the catholic is not. They interject the catholic into the verse via assumption, but it isn't there.