Judges 15:4 - Wesley's Explanatory Notes

Foxes — Of which there were great numbers in Canaan. But it is not said that Samson caught them all, either at one time, or by his own hands; for being so eminent a person, and the judge of Israel, he might require assistance of as many persons as he pleased. And it must be allowed, that the God who made the world, and by his singular providence watched over Israel, and intended them deliverance at this time, could easily dispose things so that they might be taken. He chose to do this not by his brethren, whom he would preserve from the hatred and mischief which it might have occasioned them, but by brute creatures, thereby to add scorn to their calamity, and particularly by foxes; partly, because they were fittest for the purpose, being creatures very fearful of fire; and having such tails as the fire — brands might most conveniently be tied to; and not going directly forward, but crookedly, whereby the fire would be dispersed in more places. Fire — brands — Made of such matter as would quickly take fire, and keep it for a long time; which was easy to procure. And put, &c. — That the foxes might not make too much haste, nor run into their holes, but one of them might delay another, and so continue longer in the places where they were to do execution.