en_tn/jdg/07/12.md

as thick as a cloud of locusts

Here "cloud" means a swarm. The author speaks of the army as if it were a swarm of locusts to emphasize how many soldiers there were. (See: rc://en/ta/man/jit/figs-simile)

Their camels were more ... in number than the grains of the sand on the seashore

The author uses a hyperbole, an exaggeration, to emphasize that there were very many camels. (See: rc://en/ta/man/jit/figs-hyperbole)

Their camels were more than could be counted

This can be stated in active form. Alternate translation: "Their camels were more than anyone could count" (See: rc://en/ta/man/jit/figs-activepassive)