Paradiso section 4: Puzzled by two questions regarding Constance and Piccarda, Dante idles but does not broach the subjects with Beatrice. Reading his thoughts, Beatrice first addresses Dante's question about whether souls return to the sphere of Heaven from which they were born or if all spirits live in the Empyrean (the highest level). Beatrice explains that all spirits live in Empyrean but show their faces to Dante in the sphere with which they are associated. The human intellect, Beatrice states, must perceive spirits in this manner because men need to see things to believe them. Beatrice concludes her discourse by explaining why Plato was wrong in asserting that spirits return to the stars from which they came. Next, Beatrice responds to Dante's question about the fairness of blaming people for actions that are forced against them. Beatrice explains that fault lies in the acceptance of an act rather than in the act itself. Piccarda and Constance, for example, failed to return to their convents when they were free to do so. Dante wonders if people can pay for breaking vows by doing good deeds. Beatrice directs her dazzling gaze on Dante who must turn away because of the brightness of her eyes.
Paradiso section 5: Beatrice explains that her beauty and brightness increase as they ascend in Heaven because her joy increases. Beatrice finds joy in Dante's spiritual enlightenment. Beatrice then responds to Dante's last question by explaining that good deeds can never fully compensate for broken vows because when people break vows they exercise their most precious gift from God, free will, against God. Additionally, although a vow cannot be withdrawn, the things that one promises can be replaced by other things in the ratio of six (replacement deeds) to four (deeds originally promised). Beatrice then insists that all Christians must follow both the Old and New Testament when they make vows. As Dante and Beatrice rocket to the next sphere, Beatrice's increased radiance causes the whole sphere to brighten. Dante's heart leaps with delight in response to his beloved's beauty. Dante finds himself amidst a thousand souls. Dante begs the spirits to tell him who they are and how they came to this sphere. One spirit begins to glow more brightly as it begins to speak to Dante.
Paradiso section 6: The spirit addressing Dante here in the Sphere of Mercury belongs to Justinian, a sixth-century emperor. Best known for codifying Roman law, Justinian dives into a canto-long discussion of the Roman Empire-its history and the symbolism of the eagle. Some of the historical points raised by Justinian include: the establishment of Troy in Italy by Aeneas, the defeat of Hannibal, several important wars, Augustus, Tiberius, Titus, and Charlemagne. Justinian concludes by remarking on the evil of those (the Guelphs) who wish to replace the eagle (the symbol of the Roman Empire) with the lilies of France while the Ghibellines hope to claim the eagle as a symbol for their faction alone. Dante asks Justinian to discuss the nature of the spirits that appear in this sphere. Justinian responds that these spirits belong to people who were virtuous in life but neglected God because of their desire for fame and honor. A new spirit identifies himself to Dante as Romeo. Romeo states that although he served his master well, he was driven to a life in exile by jealous courtiers.
Paradiso section 7: Still in the Sphere of Mercury, Justinian's spirit rejoins the other lights in the sky. Confused by an issue raised by Justinian, Dante wishes he could ask Beatrice to answer his questions but refuses to ask her because of her reverence for her. Beatrice, however, can read Dante's unspoken thoughts so she gladly addresses Dante's question about the nature of vengeance. Dante wonders why it was just for Titus to destroy Jerusalem if the Crucifixion was just vengeance for the sins of man. Beatrice reminds Dante of the dual nature of Christ-human and divine. The Crucifixion of the human side of Jesus was just punishment for the sins of man but the Crucifixion of the divine side of Jesus was a sacrilege. Thus, the destruction of Jerusalem was just punishment for that sacrilege against God. Beatrice then responds to Dante's second question about why God chose Crucifixion as the way to redeem man. Beatrice explains that mankind was perfect when God first created humans but fell from grace because of Adam's sins. Redemption for these sins could only come through divine mercy and there is no example of greater divine mercy than Christ's sacrifice at the cross. Finally, Beatrice explains why men are incorruptible. Her explanation justifies the notion that bodies and souls will be resurrected at Judgment Day.
Paradiso section 8: Upon seeing Beatrice's beauty grow again, Dante realizes that they have ascended to the Sphere of Venus. A spirit approaches and identifies himself as a great ruler (Charles Martel) who was loved by Dante. Martel regrets the downfall of his family at the hands of poor rulers among its ranks. Happy to see his friend, Dante asks Martel to explain how his brother could be such a poor ruler while his father was so great. Martel explains that society must have diverse characters such as judges and mechanics. Differences between father and son are created by God according to a divine scheme and any irregularities in families are due to Providence. It is bad for society for men to overturn Providence so men who are born to be clergy members must become clergy members while men born to be warriors should become warriors.