Judges 12:4-6

4Then Jephthah gathered together all the men of Gilead, and fought with Ephraim; and the men of Gilead smote Ephraim, because they said, Ye are fugitives of Ephraim, ye Gileadites, in the midst of Ephraim, and in the midst of Manasseh. 5And the Gileadites took the fords of the Jordan against the Ephraimites. And it was so, that, when any of the fugitives of Ephraim said, Let me go over, the men of Gilead said unto him, Art thou an Ephraimite? If he said, Nay; 6then said they unto him, Say now Shibboleth; and he said Sibboleth; for he could not frame to pronounce it right: then they laid hold on him, and slew him at the fords of the Jordan. And there fell at that time of Ephraim forty and two thousand.