Why General Israel Putnam said Don's fire until you see the whites of their eyes?

General Israel Putnam's instruction to "fire until you see the whites of their eyes" during the Battle of Bunker Hill emphasized the need for accurate shooting to conserve ammunition and maximize impact. At the time, American forces were outnumbered and their supplies were limited, making it crucial to ensure each shot counted. This command highlighted the importance of discipline and patience in the face of overwhelming odds, encouraging soldiers to wait for a close-range shot to increase their chances of hitting British troops effectively.