[fso301]

For the simple reason that Scripture never says we can ONLY use scripture.

And that's fine but if you rely on something other than scripture, which is generally more reliable, the opinion of an 18th century historian unversed in biblical scholarship or biblical scholars?

[verga]

which is generally more reliable, the opinion of an 18th century historian unversed in biblical scholarship or biblical scholars?

False Dichotomy. You need to rely on Sacred Tradition, the Magesterium, and the Bible, all working together.