Deuteronomy 7:20-22

Moreover, the LORD your God will send hornets among them, until those who are left and hide themselves from you are destroyed. You shall not be in dread of them, for the LORD your God is in your midst, a great and awesome God. The LORD your God will clear away these nations before you little by little. You may not make an end of them at once, lest the wild beasts grow too numerous for you.