“No wild beasts are so dangerous to men as Christians are to one another.”

Source: The Anarchist Cookbook (1971), Chapter Three: "Natural, Nonlethal, and Lethal Weapons", p. 93.

Variant: He who delights in solitude is either a wild beast or a God.

Source: Memoirs of a Geisha

De pueris statim ac liberaliter instituendis declamatio (1529), translated by Beert C. Verstraete as On Education for Children, in The Erasmus Reader (University of Toronto Press: 1990), p. 73

Les anciens Romains élevaient des prodiges d'architecture pour faire combattre des bêtes.
Letter addressed to "un premier commis" [name unknown] (20 June 1733), from Oeuvres Complètes de Voltaire: Correspondance [Garnier frères, Paris, 1880], vol. I, letter # 343 (p. 354)
Citas

Jean-Christophe (1904 - 1912), Journey's End: The Burning Bush (1911)
Context: The slaughter accomplished by man is so small a thing of itself in the carnage of the universe! The animals devour each other. The peaceful plants, the silent trees, are ferocious beasts one to another. The serenity of the forests is only a commonplace of easy rhetoric for the literary men who only know Nature through their books!... In the forest hard by, a few yards away from the house, there were frightful struggles always toward. The murderous beeches flung themselves upon the pines with their lovely pinkish stems, hemmed in their slenderness with antique columns, and stifled them. They rushed down upon the oaks and smashed them, and made themselves crutches of them. The beeches were like Briareus with his hundred arms, ten trees in one tree! They dealt death all about them. And when, failing foes, they came together, they became entangled, piercing, cleaving, twining round each other like antediluvian monsters. Lower down, in the forest, the acacias had left the outskirts and plunged into the thick of it and, attacked the pinewoods, strangling and tearing up the roots of their foes, poisoning them with their secretions. It was a struggle to the death in which the victors at once took possession of the room and the spoils of the vanquished. Then the smaller monsters would finish the work of the great. Fungi, growing between the roots, would suck at the sick tree, and gradually empty it of its vitality. Black ants would grind exceeding small the rotting wood. Millions of invisible insects were gnawing, boring, reducing to dust what had once been life.... And the silence of the struggle!... Oh! the peace of Nature, the tragic mask that covers the sorrowful and cruel face of Life!

Sejanus (1603), Act I