Context: Leaving the King's Company of actors, whose aging members, he thought, did injustice to his plays, Dryden collaborated with another playwright, Lee, and furnished manuscripts to the Duke's Company. They chose a theme magnificently treated by Sophocles, and, with less skill, by Seneca and Corneille. Dryden's addition of a subplot about the love of Adrastus and Eurydice contributed nothing to the merits or effect of the story of Oedipus and Jocasta. Unlike Sophocles, who kept Oedipus alive for a sequel, Dryden ended his tragedy with the death of the blinded king. Act III, entirely the work of Dryden, contains the magnificent incantation scene and the trial of Adrastus for the murder of Laius, late King of Thebes. Adrastus has falsely confessed, in order to take the blame from Eurydice, daughter of Laius and Jocasta. Into the setting of a sacred grove the blind prophet Tiresias enters, guided by his daughter Manto, and followed by black-clad priests. He replies to Eurydice's expressed hope that some god will protect her with the statement that everything that happens is fated. He says man is too blind to see the scales by which justice is measured and that his short measuring line and sinker cannot plumb the depths of heaven's abyss. He also uses the figure of the scales of justice with its balance bar so high above humans that they cannot see even the length of the chains hanging from either end to hold the balance pans.
TIRESIASThe gods are just;But how can finite measure infinite?Reason! alas, it does not know itself!Yet man, vain man, would with the short-lined plummet,Fathom the vast abyss of heavenly justice.Whatever is, is in its causes just;Since all things are by fate. But purblind manSees but a part o' the chain; the nearest links;His eyes not carrying to that equal beam,That poises all above.