## When they and their livestock ##

"When the Midianites and their livestock"

## they would come as a swarm of locusts ##

The Midianites are compared to a swarm of locusts because they came in with a great number of people.  (See:  [[rc://en/ta/man/translate/figs-simile]])

## it was impossible to count ##

This is a way to express the number is very great. (See: [[rc://en/ta/man/translate/figs-hyperbole]])