"After 300 years in the Promised Land, the tribes had developed unique cultures and rivalries.
The men of Ephraim were arrogant and eager to fight to seize the spoils, especially after others had won the battle (Judges 8:1; 12:1-3). They had also inherited an odd accent from an earlier ancestor who did not hear the difference between the "sh" sound and the "s" sound and passed that peculiarity on to succeeding generations. Therefore, when a person from Ephraim was asked to say the word "shibboleth," he said what he heard, "sibboleth."
As the Israelites were no longer united, they became an easy target for the pagans around them. In those days there was no king in Israel, and so they fought each other or simply stayed at home when the enemy came in like a flood.
Unity in Christ is a great strength, and disunity leads to defeat in the nation, the denomination, the congregation, and the home."