Here the word "faces" represents the men and the lions. Their faces express the fierceness with which they fight battles. Alternate translation: "who were as fierce in battle as lions hunting prey" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-explicit]])
This hyperbole compares how swiftly these men were able to run with how swiftly gazelles are able to run over rugged mountain terrain. (See: [[rc://en/ta/man/translate/figs-hyperbole]])