BARABAS:...And therefore ne'er distinguish of the wrong.
FERNEZE: Content thee, Barabas, thou hast nought but right
BARABAS: Your extreme right does me exceeding wrong. (1.2.150-52)
While Ferneze insists that he's doing justice—both in a religious and political sense—when he confiscates the Jews' property, Barabas isn't buying it. He points out that justice isn't an absolute value, and that what's "right" relative to Ferneze's beliefs and values is "wrong" relative to Barabas's.
BARABAS: For what? You men of Malta, hear me speak. She is a courtesan, and he a thief, And he my bondman. Let me have law, For none of this can prejudice my life.
FERNEZE: Once more, away with him.You shall have law. (5.1.36-40)
How the tables have turned. Now that he finds himself in a tight spot, Barabas is suddenly all about following the law. At the moment, it's the only thing standing between him and Ferneze's wrath over the murder of his son Lodowick.
JACOMO: Good Barabas, let me go
BARABAS: No, pardon me, the law must have his course. (4.1.179-80)
Marlowe's really laying on the irony here—Barabas, who's been on the wrong side of the law for basically the whole play, joys in the moment where he gets to use the law to crush his enemy Jacomo. Jacomo is in fact innocent of murdering Bernadine, but is executed anyway. So much for the course of law, huh?
JACOMO: Villains, I am a sacred person, touch me not.
BARABAS: The law shall touch you; but we'll lead you, we. (4.1.196-7)
Jacomo might as well be saying, "Do you even know who my father is?" (Where his father is, uh, the Church.) He's convinced that he's above the law because he's a friar, but Barabas knows better. Maybe there is justice in Malta.
The gold, or know, Jew, it is in my power to hang thee. (4.3.39-40)
We love blackmail. Pilia-Borza, of course, isn't going to do the hanging himself; he's counting on his ability to tattle on Barabas to the Maltese courts. So, here's the thing: sure, Barabas is guilty and should be punished. But Pilia-Borza isn't doing this out of justice; he's just using the law as a tool for his own purposes.
BOSCO: This sudden death of his is very strange.
FERNEZE: Wonder not at it, sir. The heavens are just. Their deaths were like their lives; then think not of 'em. (5.1.54-6)
Bellamira, Ithamore, Pilia-Borza and Barabas have just been thrown into prison to await "justice," which is presumably an actual trial.(Although, given what we know about how Malta works, it might just be a roll of the dice.) When they all mysteriously die, Ferneze calls it "heaven's justice." Wonder what he'd say if he knew it was really Barabas's justice?
So, march away, and let due praise be given Neither to fate nor fortune, but to heaven. (5.5.123-24)
Yeah, we're not sure that heaven's justice had much to do with Ferneze's victory. To check out the longer discussion of this quote, drop by the What's Up With The Ending? section.
Should I in pity of thy plaints or thee, Accursèd Barabas, base Jew, relent? No, thus I'll see thy treachery repaid But wish thou hadst behaved thee otherwise (5.5. 72-75)
Cue the maniacal laughter: Ferneze has Barabas right where he wants him. And check out that, even though he himself has just betrayed Barabas, Ferneze's acts don't count as "treachery" to him. Why not?
CALYMATH: Oh monstrous treason!
FERNEZE: A Jew's courtesy. For he that did by treason work our fall By treason hath delivered thee to us. (5.5.108-10)
Calymath is that Ferneze and Barabas have destroyed his army, so Ferneze obviously shifts all of the blame onto the Jew. That's easy to do in a society where treason and Judaism go hand-in-hand.