Tiresias, an old, wise seer of Thebes arrives at the palace and calls for Cadmus to come meet him. These old friends have decided to don fawnskins and worship Dionysus on Mt. Cithaeron. As they begin to dance and start their journey up the mountain, they feel a surprisingly youthful glee in their limbs. Pentheus appears on stage and does not see the old men, lost in his own thoughts, enraged as he is by the recent news of the runaway women. He considers the bacchic rites to be simply a thin veil to cover licentious, depraved and drunken behavior. As king he has already ordered the arrest and imprisonment of all the maenads, but his campaign to bring the maenads back to civilization has been made harder by the recent arrival of a foreign Dionysian wizard with long hair, wine-flushed cheeks and a large group of female followers.
As Pentheus is growling about what he will do with this enchanter's hair—once he manages to catch him—he sees his grandfather and Tiresias dressed in bacchic style and launches into a admonishing tirade against them and their foolishness. Tiresias argues back, explaining that if Demeter, an esteemed god, is the god of solid nourishment, that is, food, then Dionysus is the god of liquid nourishment, that is, wine. Dionysus's gift releases pain, brings sleep and gives joy, he explains. Further, Tiresias continues to argue that the story concerning Zeus sewing Dionysus into his thigh rests on mistaken interpretations and a confused etymology. The old, blind seer ends his response to Pentheus by concluding that Dionysus was a powerful god, master of frenzy, inspiration, panic and prophecy, and so deserves respect on account of his ecstatic power.
In reply Pentheus spitefully threatens to destroy Tiresias's religious objects and sacrificial stores. The two old men hurry away, hoping that Pentheus does not bring calamity upon the family through his unremitting rejection of Dionysus, but knowing that he will.
The chorus sings the first interlude, or Stasimon, in four parts. They first call upon Holiness, a minor deity, to witness Pentheus's sacrilegious insolence against Dionysus, and then glorify the quiet life that does not indulge folly and recklessness. In the second half of the song, the chorus talks lovingly about escaping to Cyprus, the isle of Aphrodite, where they can perform their rites in beauty and peace. This mood is invoked again in the last section where they praise Dionysus for the peace, gaiety, and moderate life he brings.
Euripides is interested not only in the nature of Dionysus but in the nature of religious belief itself, and so he provides a number of arguments both for and against worshipping the god. In Scene I the two old men articulate the wrong reasons for taking up the new religion: self-preservation and fear. Pentheus, while rejecting the worship of Dionysus, also displays the most extreme and violent form of the same tendency: self-preservation, upholding the family name and rigid rationality. The first half of the scene is also meant to be somewhat burlesque and a jibe at an overly intellectual Athenian breed of that time. Pentheus's entry is key to establishing his character and his position on the new religion. His self-absorption and short-temper are evident from the start as is his preoccupation with sex. His understanding of the Dionysian religion goes no further than the crude, tabloid, and schoolboy-fantasy level. Dionysian cults allowed women to indulge in the open expression of violent emotions, unlike 5th century Athens, which, like Pentheus, required women to be modest, self- controlled, and possessors of good sense. This ideal of female virtues also implied a certain submission to male authority. At the arrival of the Dionysian cult the city of Thebes must decide what women can and should do. Pentheus stresses authoritarian nature of this concept of femininity, whereas the chorus aims for a basic sense of good mental health and a balanced mind.
Pentheus's reaction to the old men is once more typical of his tyrannical, hotheaded and aggressive nature. One should, however, remember that, as a ruler and guardian of the state, Pentheus is somewhat justified in his desire to not just curtail but crush what he sees as a decadent and immoral cult. Tiresias's arguments in defense of Dionysus are meant to be somewhat clever and dry, as opposed to wise. Tiresias rationalizes the necessity of believing in Dionysus in two ways, first he tries to explain away the fantastical elements of Dionysus's birth as etymological confusion. Then he tries to weave the god into the established Pantheon of gods by comparing him with Demeter, and powers of other gods such as Apollo and Pan.