First, what is participating Whole Life? It is a permanent life insurance policy issued by an insurance company to an individual where dividends may be payable. A mutual insurance company is owned by policyholders as opposed to a stock company which is owned by stockholders. The benefit of mutuality is that the company is operated solely for the benefit of participating policyholders who share in the better than guaranteed investment earnings and mortality experience in these policies through the payment of annual dividends. Dividends are not guaranteed, they are declared annually by the insurer's board of directors.
A Whole Life policy is a unilateral contract between the policyholder and the insurance company. It promises that if the policyholder pays the specified premium, then a specified death benefit will be paid and that the cash value within the policy will equal the death benefit at a specified age (at which point the policy is said to "endow")