The most formidable of the inhabitants of Canaan were the Philistines (cf. Palestines).
The Philistines were intimidating for a number of reasons, most notably for their great warrior, Goliath, who stood 10 feet tall.
The Philistines offered a challenge to the Hebrews. A one-on-one contest that would decide the outcome of the war. Whichever warrior won would mean victory for his team.
None of the Hebrew warriors were willing to accept the challenge.
A boy named David, who was a singer and a harpist, volunteered to take on Goliath. He offered his services to King Saul.
DECISION: You are King Saul. Do you accept David's invitation?
Military Concepts:
underdog
vulnerability
preparation
divine assistance