Final answer:
David removed his armor due to his youth and to demonstrate that his victory over Goliath was achieved through faith and ingenuity, not traditional warfare. Both Donatello's and Bernini's sculptures of David emphasize his youthful determination in the face of an overwhelming challenge.
Step-by-step explanation:
David took off the armor because it symbolized that he was unsuited for traditional warfare due to his youth and that his victory would come through his faith and cunning rather than conventional means. Donatello's David and Bernini's David highlight different aspects of the story, but both stress David's youth and the unexpected nature of his triumph. Donatello depicts David with unformed musculature, shepherd's hat, and boots, emphasizing his youth and innocence. The allusion to the acceptance of physical relationships between older Florentine men and younger boys may signal David's youth and vulnerability. Bernini's sculpture portrays David in motion, a dynamic representation of his determination and the physicality of his actions. His body is twisted in action, a departure from the calm poise of classical statues, evoking a sense of the dramatic moment before David's triumph over Goliath.