It is not written (Exodus 15:7) "He has consumed them as stubble," but "He will consume them as stubble" — in time to come, viz. (Ovadiah 1:18) "And the house of Yaakov will be fire, and the house of Joseph, flame, and the house of Esav, stubble, and they will ignite them and consume them, etc." And it is written (Zechariah 12:6) "On that day I will make the chieftains of Judah like a stove — fire (burning) wood, torch (burning) sheaf, etc."