Dionysus: "Yes, here in Hellas, Thebes is the first city I fill with the transports of ecstatic women." (1)
Dionysus has greatly upset the societal order of Thebes with his shenanigans. Not only has he driven people mad and sent them off to dance in the woods, but these particular people are women. This sort of behavior was totally against the rules for females in Greek society.
Tiresias: "No, we don't play at theologians with the gods. We stay close to the hallowed tenets of our fathers, old as time. Nothing can undo them ever." (19)
Though Tiresias and Cadmus are violating the rules of the city by heading off to worship Dionysus, they are staying true to a much older set of regulations the rules of the gods. Both old men have seen enough life to know the terrible penalties that the gods put on humans who don't respect them.
Pentheus: "The ones [Maenads] I've rounded up, my police have handcuffed and safely clapped in jail." (21)
Upon his return to the city, Pentheus wastes no time trying to reassert himself. He's locking up Bacchus-crazed women left and right. Though he probably comes off as kind of a jerk, he's mostly just doing his job. What's a king to do when he comes home and finds every woman in his city dancing wildly in the woods? Isn't he expected to maintain order in the city?
Pentheus: "From me you do not have a thing to fear. It is never right to fume at honest men." (118)
Pentheus assures the Herdsman that it is OK for him to tell the whole story of the Maenads even if it the tale contains things the King doesn't want to hear. Though he seems to come off as angry and closed minded for most of the play, this hints that he previously ran Thebes in a pretty rational and even-tempered way. It's only towards anarchy of Dionysus that he gets all cranky. It seems that Pentheus is a man who greatly values order.
Herdsman: "They [Maenads] tore like an invading army through the villages […] They snatched up babies out of homes. They carried fire on their flowing heads and it did not burn them." (119)
Looks like Pentheus has got a full-blown case of anarchy going on. Once you've got baby snatching and flaming-headed ladies running round, there's no denying it. By trying to suppress the celebrations of the Maenads he's caused disorder in the entire countryside.
Dionysus: "I'm your lady's maid." […] Pentheus: "There you dress it. I'm all yours now." Dionysus: "Tch! Tch! Your girdles loose, And your skirts all uneven at the ankles." (183-185)
Here, both Dionysus and Pentheus are taking on feminine roles. Dionysus play acts at being a lady in waiting, while Pentheus acts like a straight up princess. This blurring of the lines between male and female is another example of the way that Dionysus shatters the carefully ordered social structure of Thebes.
Chorus: "Let Justice sworded walk To strike through the throat and kill this godless ruthless lawless man" (211)
It's interesting that the Chorus describes Pentheus as lawless. He'd probably say the same the thing about them. The Chorus, like Tiresias and Cadmus, adhere to a different set of laws than Pentheus – the laws of the divine.
Leader: "Tell it all. Explain exactly how he died-- this perverse man, this purveyor of perversion." (224)
Pentheus constantly accuses the Bacchants of perverting the order of society, with their crazed revelries. Here, however, we see the Chorus call him the pervert. They see Pentheus's lack of fealty to Dionysus as the true perversion of what is right and good.
Pentheus: "Have mercy on me, Mother, and because of my mistakes do not kill your son--your son." (225)
Many Greek tragedies center around the violation of a pretty fundamental law. One of the most popular no-no's for a tragedian to write about was one family member killing another. Oedipus killed his father. Clytemnestra killed her husband. Orestes killed his mother. The list goes on. In The Bacchae we have a mother killing her son. What's interesting is that this horrific act is god sanctioned, and in fact isn't the choice of the mother at all. What makes it even more messed up is that Dionysus himself is related to these people. Pentheus is his cousin and Agave is his aunt.
Dionysus: "My father sanctioned this [punishment] in ages past, great Zeus." (316)
In the end, it is the will of the gods that is triumphant. The rules and laws of man prove to insignificant in the face of the gods' ancient decrees. Pentheus brings his entire household to ruin by attempting place his own idea of order over that of Dionysus.