[Resettozero]

If scripture alone were entirely sufficient...

...which It is, there would be no need of Roman Catholic church leaders historically to add to, delete from, and otherwise alter the clear meaning of the Holy Bible, or to hide the Bible from its customers.

[D-fendr]

If scripture alone were entirely sufficient...which It is

That doctrine is not in Holy Scripture, so it fails its own test.

It's also not possible in practice of determining doctrine. You take the place of the Church in determining doctrine on your own authority or according to your own tradition.