Marx: Labor=Product

When we were discussing Marx I found his idea that labor should be equal to the product to be very obviously implausible. Marx questions that if this is the truth then why is their a surplus value or profit? But if the value of labor is in fact equal and there is no profit then there can be no incentive or reason to produce a product or employ a "free laborer" in the first place. If there is no monetary gain for a company from producing a product then no one profits in the equation and it becomes redundent.