What are the Biblical arguments against man having an immortal soul separate from the body?

Belief in an immortal soul seems quite common in Christianity although some denominations do not seem to believe in this. What specific scriptures, and scriptural arguments, are used by those that do not believe in humans having an immortal soul separate from the body? **Update:** this is not a duplicate of this other question because this one is specifically asking for support for the opposite viewpoint. Additionally the other question has only answers which support the idea that humans **do** have a soul. If this **has** to be scoped to a particular denomination, I choose Jehovah's Witnesses.