Bible alone believers do not require non-biblical writings like catholic magisterium & catechism to understand what the Bible alone teaches.
No, they only require their own understandings, shaped by their own personal disposition and up bringing in their culture, which is a far cry from the faith being handed down starting by the apostles to the next generation, then to the next right throughout history to today
The bible is not meant to be a personal book, of how one understands it
You will need to prove that what you understand from the bible is actually what the bible is actually conveying. its a simple fact of life, the bible is extremely complex for one person to understand, all the Gospels and letters are addressed to communities.
The fact of the matter is the bible is infallible, God's word, but interpretation is not, the 30000 different denominations going bible alone itself shows "Bible alone believers" is nothing but an ideology that simply doesn't work, no matter how much one repeats it or think it's all that is needed.
