What's that obvious fact? Namely that Saint Augustine was a big-C Catholic, not a "proto-Calvinist," as many in the Reformed camp delude themselves into believing.
I know that seems obvious. But there are some Reformed folk, like the prolific R. C. Sproul, who think of St. Augustine as a sort of pre-Calvinist. But, as Tim A. Troutman points out in his Called to Communion piece, "Augustinian Soteriology," nothing could be further from the truth. Here's an excerpt:The point I want to draw out is that the Reformation’s favorite early saint sharply disagrees with the Reformers on what they called the central issue. The other points where Reformed thought diverges from Augustine are important too; but let’s start here.
If it is true, and Augustine, the supposed proto-Reformer, holds the Catholic view of cooperation, then what does that mean for the case of the Protestant community? After all, notice above that the Catholic Church doesn’t quote Augustine in support of the Catholic view, she simply quotes Augustine as the Catholic view itself.
You can read the whole thing here. For even more detail on this matter, see Troutman's other piece, "Soli Deo Gloria." (Source)