Apostolo Zeno defined the form of the oratorio by giving it unity of action, time and place, and strict dramatic treatment, and Metastasio carried on and completed the work just as he had done in the opera. Its division was into two, not three parts, otherwise the arrangement corresponded altogether with that of the opera. The characters enter speaking; recitative is employed for the dialogue, and the airs serve {"LA BETULIA LIBBRATA," 1773.} (195) to express the higher emotions; concerted songs occur but seldom, but the choruses are frequent, and more often form a part of the action than in the opera. The subject-matter is borrowed from the Bible, generally the Old Testament, or from some old legend; but both persons and plot must of necessity be devised, so as to represent the story in a succession of dialogues. An effort is made to preserve the biblical diction in the poetry, but the animated rhetorical style of Italian poetry decidedly gets the upper hand. Moral and religious reflections are the almost invariable themes of the songs and choruses, which have rarely any individual character. In this respect, as well as in the dearth of dramatic action, the azione sacra comes nearer to the so-called azione teatrale than to the genuine opera seria. The legend of Judith is treated as follows by Metastasio, in his oratorio "La Betulia Liberata," which has often been composed.[13]The _dramatis persona_ ("interlocutori") are:--[See Page Image] Ozia reproaches the desponding inhabitants of Bethulia for their cowardice, and declares his resolution not to give up the city to the enemy. Amital and Cabri oppose him, describing the sufferings of the people from famine and sickness. In vain he reminds them how the Lord has helped their fathers, they demand admission to Holofernes, and it is with difficulty that he obtains a delay of five days, and calls upon God for help, with the chorus. Then Judith enters; horrified at {ORATORIO.} (196) the decision, she upbraids them for their cowardice which dares to doubt God's mercy and set a limit to His power: "il primo è vile, temerario il secondo." Her song (5) may serve as a standard for the style of this poetry: Del pari infeconda D' un flume è la sponda, Se torbido eccede, Se manca d' amor. Si acqaista baldanza Per troppo speranza, Si perde la fede Per troppo rumor.