Chesterton on Deus Caritas Est

[T]here is no saying which the humanitarians of a broad religion more commonly offer as a model of simplicity than that most mystical affirmation "God is Love." And there is no theological quarrel of the Councils of the Church which they, especially Mr. Wells, more commonly deride as bitter and barren than that at the Council of Nicea about the Co-eternity of the Divine Son. Yet the subtle statement is simply a metaphysical explanation of the simple statement; and it would be quite possible even to make it a popular explanation, by saying that God could not love when there was nothing to be loved.
-- G.K. Chesterton, The New Jerusalem (1920)

If there is one question which the enlightened and liberal have the habit of deriding and holding up as a dreadful example of barren dogma and senseless sectarian strife, it is this Athanasian question of the Co-Eternity of the Divine Son. On the other hand, if there is one thing that the same liberals always offer us as a piece of pure and simple Christianity, untroubled by doctrinal disputes, it is the single sentence, 'God is Love.' Yet the two statements are almost identical; at least one is very nearly nonsense without the other.
-- G.K. Chesterton, The Everlasting Man (1925)

The faith in a future life, the hope of a future happiness, the belief that God is Love and that loyalty is eternal life, these things do not produce lunacy and anarchy, IF they are taken along with the other Catholic doctrines about duty and vigilance and watchfulness against the powers of hell. They might produce lunacy and anarchy, if they were taken alone.
-- G.K. Chesterton, The Thing (1929)