Judges 12:5-6

In order to keep the Ephraimites from escaping, the men of Gilead captured the places where they could cross the Jordan. When any Ephraimite tried to escape and asked permission to cross the river, the men of Gilead would ask, “Are you an Ephraimite?” If he said, “No,” they would tell him to say “Shibboleth.” But if he could not pronounce it correctly and said “Sibboleth,” the men of Gilead would seize him and kill him there at the crossing place of the Jordan. At that time, they killed forty-two thousand Ephraimites.