Moreover, the LORD your God will send hornets among them, until those who are left and hide themselves from you are destroyed.
Deuteronomy 7:20 ESV

When you believe your enemy defeated, you cannot stop obeying God. There is always another enemy hiding. Continue in obedience because you don't know what is going on in the shadows and hidden places.

Hornets are not literal, but a metaphor of panic caused by both physical and spiritual threats.