For they intended evil against thee. Their destruction is brought upon them by their own selves. They plot against the people of God, and thus provoke God to anger, and cause him to deliver them into their enemy' s hand.
It does not matter that they can effect nothing. The "intention" is enough. They imagined a mischievous device, which they are not able to perform. The inability is not so much from a deficiency of strength in themselves, as from the opposition offered to their schemes by God.
The best-laid plans an powerless, if God wills to baffle them.