There is nothing in the Bible mandating sola Scriptura.
Actually, Christ did tell us not to store up treasures on earth, where moth and rust do corrupt and thieves break in and steal, but to store up treasure in heaven. That could be clearly understood as “adding to the treasury of grace,” in my opinion.
I’m going back to find that poster who mentioned adding to the treasury of Grace, and thank him/her.
There's nothing in the bible that says someone who doesn't believe the bible would be able to understand it...In fact, quite the contrary...