Dionysus: "You see, they should have […] known better […] my mother's sisters, who said that I, Dionysus, was no son of Zeus" (1)
That's the understatement of the century. The fact that his mortal relatives deny that Dionysus is actually a god is the conflict brewing at the heart of the play. All the horrible blood and mayhem that we see is a result of this religious difference.
Cadmus: "I'm all ready, see, complete in Dionysiac trappings. And why not? He's my own daughter's child" (8)
Wouldn't it be a little weird if one of your relatives was a god? That's the situation that old Cadmus is in. Here we see him embracing the new religion of his grandson. Unlike Pentheus and the rest of his family, Cadmus totally buys into the divinity of Dionysus. Of course, this doesn't help at all by the end of the play. He's punished too.
Pentheus: "She'd [Semele] had the nerve to name Zeus the Father as her lover…What gall! What effrontery!" (21)
Notice that Pentheus is not blasphemous towards all gods. It's just Dionysus that he has a problem with. He is offended by the idea that Semele, his aunt and Dionysus' mother, was the lover of Zeus. Perhaps this shows a dedication to Zeus, the Greek king of the gods. In the Greek mind, however, it was important to pay homage to all gods, because anyone of them could deal out punishment.
Tiresias: "He [Dionysus] is a god of prophecies […] He also has assumed some of Ares' duties A regiment in arms, for instance" (22)
To the ancient Greeks, it was totally cool for gods to share duties. It seems that Dionysus is now influencing both prophecy, which was previously an Apollo thing, and war, which was mostly Ares's job before that.
Pentheus: "Rituals of possession of ? Of what particular form? […] You make me want to hear." (42-46)
Pentheus seems really interested in the particulars of a religion that he claims is a load of garbage. Is he really as sure of the falseness of Dionysus as he says he is? In any case, it's this curiosity that eventually leads him to his grisly death.
Herdsman: "great lordly bulls, one minute glaring in all the pride of their horns, the next dragged to ground like carcasses by the swarming hands of girls." (119)
One the symbols of Dionysus was the bull. Later in the play he even appears to Pentheus as one. Given that, it's interesting that it was also common for bulls to be sacrificed in his rituals.
Herdsman: "After all this my lord, whoever this city be you must receive him in our city. He is powerful in many things." (119)
The Herdsman has witnessed the raw power of Dionysus and wisely advises Pentheus to pay honor to the god. Of course, the King refuses. We wonder what has turned Pentheus so steadfastly against Dionysus. Is it just that their philosophies of life are so different? Is Pentheus jealous that his cousin was born a god and not him?
Chorus: "Slowly but surely divine Power moves to annul The brutally minded man Who in his wild delusions refuses To reverence the gods." (173)
A constant theme throughout Greek tragedy is the price men pay for blasphemy. In play after play, we see heroes and heroines punished for disrespect to the gods. It's interesting that the theme figured so prominently in this play by Euripides, who some scholars believe was an atheist.
Chorus: "As to the rest, the sublime is simple and leads To a beautiful life, […] It sheds from it everything wrong In pursuit of the right a And homage to heaven." (212)
The Chorus sings a song of devotion to the divine. To them, the life they've chosen is the true path to the sublime. They've given up everything for their god, shedding everything in the name of Dionysus.
Agave: "But gods should not repeat the passions of mere men." (315)
Yeah, maybe, but this doesn't seem to be true at all with the gods of the ancient Greeks. They act pretty much exactly like people. They betray each other, fight amongst themselves, and fall in love. The only real difference is that they have a ton of power. It's really no wonder the Greeks were busy trying to be humble all the time. With the world of the divine in such tumult all the time, you had to be really careful not to anger any divine entity.