Ten Homilies on the First Epistle of John - Saint Augustine of Hippo

As regards the plan of the Epistle, it has been often asserted till lately that it was supposed to be but fragmentary, a series of aphorisms. Augustine, however, without formally announcing a plan as discovered by him in the Epistle, not only frequently affirms in his exposition that charity or love is the Apostle’s main theme, but so conducts the discussion, gathering his arguments and illustrations around this central thought, as to render it evident that in his view the purpose and plan of the Apostle is to set forth love in its essence and its scope, and that he intends to make this thought dominant in every part. - Summary by Philip Schaff