As a former baptist, there was a particularly powerful argument that helped me consider (and eventually convert to) the authority of the Church. First, I considered the period when bible was canonized. As I read the how’s and who’s of it’s formation I was forced to consider what the church looked like back then. I realized that there was really only one church at that time, the Church, and that Church is still here. I couldn’t shake that concept and was forced to admit that my source of authority, the Holy Bible, came from a greater source, the Church with Jesus as the head.
With the authority of the Church nailed down, seeing the papacy in the Catholic light was relatively easy. I’ve never looked back.