The snake has very sharp eye sight and is indeed a very cunning creature. Scripture here tells us to imitate the snake. To be shrewd as a snake and protect ourselves from the insults and rage of men. We're also not to expose ourselves unnecessarily to dangers and avoid all snares, traps which might be laid for us. And at the same time to be innocent and as harmless as doves. Meaning we should be free from all wicked cunning, craftiness, malice, and wrath. Not be revengeful people but rather meek & humble and lead inoffensive lives.