“Thou shalt leave each thing
  Beloved most dearly:  this is the first shaft
  Shot from the bow of exile.  Thou shalt prove
  How salt the savor is of other’s bread;
  How hard the passage, to descend and climb
  By other’s stairs.”

Then Cacciaguida goes on to state that Dante shall finally find refuge in Lombardy, with Can Grande, and while there will compose the poems depicting his memorable journey down through sin to the lowest pit and upward through repentance to the realm of bliss.

  “For this, there only have been shown to thee,
  Throughout these orbs, the mountain, and the deep,
  Spirit, whom fame hath note of.  For the mind
  Of him, who hears, is loath to acquiesce
  And fix its faith, unless the instance brought
  Be palpable, and proof apparent urge.”

Seeing Dante’s dismay at this prediction, Beatrice comforts him by a smile, and, seeing he is again wrapped in contemplation of her, warns him that “these eyes are not thy only Paradise.”

Canto XVIII. Then Beatrice leads her charge into the fifth heaven, that of Mars, revolved by Virtues and inhabited by transfigured martyrs, confessors, and holy warriors, such as Joshua, the Maccabees, Charlemagne, Orlando, Godfrey of Bouillon, and other men of note.  These worthies form a part of the mystic cross, and each glows with transcendent light as Beatrice points them out one after another.  Then Beatrice wafts her change into the sixth heaven, that of Jupiter (revolved by Dominations).  Here the spirits of rulers famous for justice, moving with kaleidoscopic tints and rapidity, alternately form mystic letters spelling “Love righteousness ye that be judges of the earth,” or settle silently into the shape of a gigantic eagle.  This sight proves so impressive that Dante sinks to his knees, fervently praying justice may indeed reign on earth as in heaven.

Canto XIX.  To his intense surprise Dante now hears the mystic eagle proclaim in trumpet tones that justice and pity shall be exacted, and that no man shall be saved without them.  He adds that eternal judgment is incomprehensible to mortal ken, that mere professions are vain, and that many so-called Christian potentates (some of whom he names) will present a sorry figure on Judgment Day.

Canto XX.  After a period of silence, the same Eagle (an emblem of the Empire) proceeds to exalt certain rulers, especially those glorified spirits which form the pupil of his eye (David), and his eyelids (Trajan, Hezekiah, Constantine).  As he mentions their names they glow like priceless rubies, and he explains that, although some of them lived before Christ was made flesh, all have been redeemed because Faith, Hope, and Charity are their sponsors.