Extreme justice is extreme injustice.
In Latin, Summum jus, summa injuria. Full attribution: Cicero, De Officiis (44 BC), I. 10. Also in De Republica. V, Chapter III. Same idea in Aristotle—Ethics. V. 14. Terence—Heauton timorumenos, Act IV, scene 5. 48. Columella—De Re Rustica, Book I, Chapter VII. (Ed. Bipont, 1787.) Racine—La Thébaide, Act IV, scene 3. Les Frères Ennemis, IV. 3.