They have sharpened their tongues like a serpent,.... Which Kimchi says it does before it bites. Aristotle observes, that the tip or extreme point of a serpent's tongue is as small as a hair, and so exceeding sharp and piercing.
Arama interprets this of the sharpness and cunning of the serpent; and particularly the serpent that deceived Eve, and spake cunningly to her. "For God knoweth", &c.