6. And so we prepare to commence this our Fifth Book, O Emperor Augustus. For it was but right that the Fourth Book should end with our discussion on the Vine, lest otherwise we should seem to have overloaded that book with a tumultuous mass of subjects, rather than to have filled it with the fruit of the spiritual vineyard. On the other hand, it was not seemly that the gathering of the vintage of the faith should be left unfinished, whilst there was still all abundance of such great matters for discussion.