Actually, only a carnal people would think such and that is what Augustine says.
One must first believe and then know.
So, those who believed Jesus is the Son of God, then knew that what He said is true, whether they could understand it or not.
If one does not understand the union of the carnal and the spiritual, it is because one does not believe that Jesus could give us His flesh to eat and His blood to drink.
Well, it’s been interesting.
Good night and God bless.