Canto III Dante and Virgil encounter the souls of the excommunicate, those who died repentent but out of communion with the Church. They must wait to attain Purgatory proper, but have a firm hope of final salvation. The souls tell the poets where they will be able to climb up the mountain, which presents them, where they stand, with a sheer cliff.

The theme of this canto is community. Early on Dante, forgetting that Virgil lacks a material body, notices his own solitary shadow and fears that he has been abandoned. Dante at that moment feels acutely isolated and fearful. The souls that they meet have put themselves out of the community of the Church, the community in which salvation is achieved because salvation is never a purely individual matter. They appear in Dante's description as “sheep without a shepherd” timid and uncertain. They lack a prayer of their own, unlike almost all the other categories of souls which the poets encounter, since prayer, too, is never entirely an individual matter. However, they are not without hope, and the first rekindled sparks of community life can be seen among them. They can also benefit from the prayers of the Church, the community that they are rejoining. This is explained by one of their number, the prince Manfred, who requests that Dante ask for the prayers of his relatives on his behalf. They also offer help to Dante in Virgil in their continuing journey.