Why did Chauvelin have the Jew beaten?

Chauvelin has promised the jew that if he betrayed his promise he would be beaten.... he deceived Chauvelin and was beaten.

It was agreed between us, that if we overtook my friend the tall stranger, before he reached this place, you were to have ten pieces of gold.” A low moan escaped from the Jew’s trembling lips. “But,” added Chauvelin, with slow emphasis, “if you deceived me in your promise, you were to have a sound beating, one that would teach you not to tell lies.”

“I did not, your Honour; I swear it by Abraham . . .”

“And by all the other patriarchs, I know. Unfortunately, they are still in Hades, I believe, according to your creed, and cannot help you much in your present trouble. Now, you did not fulfil your share of the bargain, but I am ready to fulfil mine. Here,” he added, turning to the soldiers, “the buckle-end of your two belts to this confounded Jew.”

As the soldiers obediently unbuckled their heavy leather belts, the Jew set up a howl that surely would have been enough to bring all the patriarchs out of Hades and elsewhere, to defend their descendant from the brutality of this French official.

“I think I can rely on you, citoyen soldiers,” laughed Chauvelin, maliciously, “to give this old liar the best and soundest beating he has ever experienced. But don’t kill him,” he added drily.