Final answer:
David left his supplies with the keeper of supplies in the Valley of Elah before going to fight Goliath, as described in 1 Samuel 17:22.
Step-by-step explanation:
The Valley of Elah is well known as the site of the famous battle between David and Goliath from the Bible. However, in the context of your question, which is asking about where David left his supplies before a battle, the account you are looking for is actually in 1 Samuel 17:22. It says that David left his supplies with the keeper of supplies before heading out to the battle lines to face Goliath. Although other verses from Samuel and Kings recount various events of battle and leadership involving David, this particular incident in the Valley of Elah highlights David's humble beginnings and trust in God as he prepares to face a daunting foe.