John Wesley on Numbers 13:32

Eateth up its inhabitants - Not so much by civil wars, for that was likely to make their conquest more easy; but rather by the unwholesomeness of the air and place, which they guessed from the many funerals, which, as some Hebrew writers, not without probability affirm, they observed in their travels through it: though that came to pass from another cause, even from the singular providence of God, which, to facilitate the Israelites conquest, cut off vast numbers of the Canaanites either by a plague, or by the hornet sent before them, as is expressed, Jos 24:12.