Dante exposes Virgil before passing through the gates of hell. It is Virgil himself who invites Dante to take a tour of hell, purgatory and paradise. Virgil is introduced as a messenger, as he was sent by Dante's beloved, Breatriz to accompany him on this tour.
He is shown in corner 1 as a great connoisseur of the circles of hell, as well as a great encourager, since it is he who prevents Dante from giving up in the face of his fears.
These characteristics of Virgil, make the reader have a certain comfort when facing Dante's terrifying neighbors, because Virgil is represented as a companion and this companionship is felt by the reader.