Rashi on Deuteronomy 1:44/רש"י על דברים א׳:מ״ד

1כאשר תעשינה הדברים [AND THEY PURSUED YOU] AS BEES DO — Just as a bee when it stings a person it dies immediately, similarly they (the Amorites): when they attacked you they died immediately (Numbers Rabbah 17:3).