Even Virgil is pale with fear at being refused entry to the city of Dis. He voices a worry that the angel coming to help them is taking too long. Dante asks him if anyone has made this journey past the gate before and Virgil tells him that he did once before, when he was sent to fetch a soul from the deepest, darkest circle of hell. Virgil reassures Dante that he knows the way.
Dante is beginning to have doubts about his journey, even though it is willed by heaven. Like Dante's excessive pity, this could be seen as an affront to God's divine plan. However, even Virgil is fearful at this moment.
Virgil keeps talking, but Dante stops following what he is saying, as he is distracted by the tops of the towers of Dis, glowing with flames. There, he sees three female figures appear: the Furies. They are covered in blood and have snakes around their brows. Virgil instantly recognizes them and names them individually: Allecto, Megaera, and Tisiphone. The furies shriek loudly and call for Medusa to come and turn the two poets to stone. Virgil tells Dante to cover his eyes, because if he is turned to stone by Medusa he will be trapped in hell forever.
Virgil's words again fail to have their usual effect on Dante here. The Furies and Medusa are monsters from classical mythology (hence easily recognizable for Virgil), whom Dante places in his frightening hell. It seems that the forces of hell may overwhelm Dante and Virgil, may turn them to stone and trap them in hell…
But just then, Dante hears a loud crashing noise and turns to see an angel coming toward them across the Styx, walking on water and parting the crowd of souls in its way. The angel touches the gate with a wand and it opens instantly, with no resistance. The angel tells the inhabitants of Dis to stop trying to thwart the will of God, and then leaves without speaking to Dante or Virgil.
… but then the angel almost effortlessly clears the way for Dante and Virgil, sending the Furies and fallen angels away with the power of its speech. The angel's ease in opening the door despite the resistance of the fallen angels, furies, and others reasserts even more clearly the absolute might of God's divine will.
Under the protection of the angel's words, Dante and Virgil proceed into Dis. Dante looks around and sees a plain filled with sepulchers, with flames flaring up in between them. The tombs are left open and are burning in the flames. He hears screams from those inside the tombs.
The protection offered by the angel is through its words, which are in some sense a proxy for the very word of God. As Dante and Virgil go deeper into hell, the punishments become more extreme as they are perfections of more extreme sins.
Dante asks Virgil who these people are in the burning tombs, and Virgil says that they are "heresiarchs", leaders of heretical sects and their followers. The two poets continue on their journey, walking past the blazing tombs.
Heretics deliberately defy God and, as such, are denied the ease of death—they are placed in tombs in which they live and burn indefinitely. Later in the Inferno Virgil will explain to Dante why some sinners exist within Dis while others (those Dante has encountered up until now) are punished outside the walls of Dis.