I will send serpents - These were symbols of the enemies that were coming against them; a foe that would rather slay them and destroy the land than get booty and ransom.
I will send - Or, am sending. No prophet changes his metaphors so suddenly as Jeremiah. The invading army is now compared to snakes, whom no charming can soothe, and whose bite is fatal. Compare Numbers 21:5-6.
Cockatrices - “Vipers.” See Isaiah 11:8 note.