He injects his deadly venom when you are least expecting it. You may not even feel his fangs sinking into your most vulnerable part. But you'll suffer when the poison works. If he is a boa-constrictor rather than a venomous snake he may wrap himself round you and squeeze you to a slow, agonising death. As in the Bible, the Snake relies on lying to bring about his results.
Lies are extremely difficult things to deal with.
First, you probably don't know that you are being lied about. Second, a lie doesn't have to be specific. But think about it. It is a totally meaningless phrase. It is nonsense.