Final answer:
The Book of Jonah is chosen for the Yom Kippur afternoon service as it reflects on themes of repentance and divine mercy relevant to the day's focus on atonement.
Step-by-step explanation:
The Book of Jonah is chosen as the haftorah for mincha on Yom Kippur due to its themes of repentance and divine mercy. Jonah's story, involving his flight from God's command, his entrapment in the belly of a great fish, and eventual delivery of a warning to the city of Nineveh which leads to its repentance, aligns with Yom Kippur's central themes.
The day is the holiest in the Jewish calendar, dedicated to atonement and repentance. Reading the Book of Jonah serves as a reminder that everyone has the opportunity to repent and be forgiven. The symbolic significance of repentance and personal reflection throughout Jonah's narrative complements the spiritual introspection and communal repentance that characterizes Yom Kippur.
Therefore, this prophetic reading is an essential complement to the day's liturgical themes.