The answer is: Held out his spear towards Ai

Josh 8:18 - Described as a javelin in some versions

In the thrilling battle of Ai, Joshua's strategic brilliance shines through, especially with his signal of holding out a spear toward the city. In this context, the spear symbolizes authority and divine approval, mingling military prowess with the spiritual. It’s noteworthy that the Hebrew word here can refer to either a spear or a javelin; this ambiguity adds an element of both mystique and flexibility to our understanding of ancient warfare gear.

Picture the scene: Joshua stands visible on the hillside, raising either his weapon of choice or a different leaping javelin as a beacon for his troops. This moment echoes the way Old Testament leaders facilitated communication on the battlefield through divine signs. For instance, Moses raised his hands during the battle against Amalek to signify Israel’s need for help (Exodus 17:11). Such motifs of collective action, where victory correlates directly with obedience to divine commandments, flicker throughout the Hebrew Scriptures.

Interesting trivia: Ai means "heap of ruins," and true to its name, it remained one of the most debated archeological sites due to the layers of destruction levels found there that might correspond to intense conflict seasons. Utilizing archeology harmonizes captivating evidence of battles specified in the Bible and allows relatable connections in examining historical narratives. So as with Joshua, there are vital lessons embedded regarding strategy, faith, and leadership that extend beyond the battle itself. It is the merger of faith and the forthright preparation we see, echoing lessons for countless passages still relevant today.