Canto XV. Circling round the mountain, always in the same direction, Dante notes the sun is about to set, when another dazzling angel invites them up to the next level,—­where anger is punished,—­by means of a stairway less steep than any of the preceding.  As they climb, the angel softly chants “Blessed the merciful” and “Happy thou that conquer’st,” while he brushes aside the second P ., and thus cleanses Dante from envy.  But, when Dante craves an explanation of what he has heard and seen, Virgil assures him that only when the five remaining “scars” have vanished from his brow, Beatrice herself can satisfy his curiosity.

On reaching the third level, they find themselves enveloped in a dense fog, through which Dante dimly beholds the twelve-year-old Christ in the Temple and overhears his mother chiding him.  Next he sees a woman weeping, and lastly Stephen stoned to death.

Canto XVI. Urged by his guide to hasten through this bitter blinding fog—­a symbol of anger which is punished here—­Dante stumbles along, mindful of Virgil’s caution, “Look that from me thou part not.”  Meanwhile voices on all sides invoke “the Lamb of God that taketh away the sins of the world.”  Then, all at once, a voice addresses Dante, who, prompted by Virgil, inquires where the next stairway may be?  His interlocutor, after bespeaking Dante’s prayers, holds forth against Rome, which, boasting of two suns,—­the pope and the emperor,—­has seen the one quench the other.  But the arrival of an angel, sent to guide our travellers to the next level, soon ends this conversation.

Canto XVII. Out of the vapors of anger—­as dense as any Alpine fog—­Dante, who has caught glimpses of famous victims of anger, such as Haman and Lavinia, emerges with Virgil, only to be dazzled by the glorious light of the sun.  Then, climbing the ladder the angel points out, Dante feels him brush away the third obnoxious P., while chanting, “Blessed are the peacemakers.”  They now reach the fourth ledge, where the sin of indifference or sloth is punished, and, as they trudge along it, Virgil explains that all indifference is due to a lack of love, a virtue on which he eloquently discourses.

Canto XVIII. A multitude of spirits now interrupt Virgil, and, when he questions them, two, who lead the rest, volubly quote examples of fervent affection and zealous haste.  They are closely followed by other spirits, the backsliders, who, not having had the strength or patience to endure, preferred inglorious ease to adventurous life and are now consumed with regret.

Canto XIX. In the midst of a trance which overtakes him, Dante next has a vision of the Siren which beguiled Ulysses and of Philosophy or Truth.  Then, morning having dawned, Virgil leads him to the next stairway, up which an angel wafts them, chanting “Blessed are they that mourn, for they shall be comforted,” while he brushes away another sin scar from our poet’s forehead.