Judges 12:5,6 - Joseph Benson’s Commentary on the Old and New Testaments

If he said, Nay To avoid the present danger. Then said they unto him, Say now Shibboleth To find out the truth, they put him to this test; whether his pronunciation of some words was like that of the Gileadites; for people of the same nation, who speak the same language, generally differ very much in the pronunciation of it, according as they live in different parts of the country. As the word signifies a stream or river, and they desired to pass over one, it was a word proper for the occasion, and gave them no cause to suspect the design, because they were only desired to say, “Let me go over the Shibboleth or river.” And he said, Sibboleth If he was an Ephraimite, he presently discovered himself, for he could not pronounce the Hebrew letter שׁ, shin; which probably proceeded from the long habit of that people, to express themselves in a different manner; so that they could not readily frame the organs of speech to pronounce as the Gileadites did. The Hebrew text, however, does not say that he could not, but that he did not frame to pronounce it right; because, not suspecting the design, he uttered hastily, according to his usual manner of expression. There fell forty and two thousand Not in that place, but in that expedition, being slain either in the battle, or in the pursuit, or at Jordan. See the justice of God! They had gloried that they were Ephraimites; but how soon are they afraid to own their country! They had called the Gileadites fugitives; and now they are in good earnest become fugitives themselves. It is the same word (Jdg 12:5) used of the Ephraimites that fled, which they had used in scorn of the Gileadites. He that rolls the stone of reproach unjustly on another, it may justly return upon himself.