The principle of mutuality is rooted in common sense. A person cannot make a profit from herself. This implies that a person cannot earn profit from an association that he shares a common identity with. The essence of the principle lies in the commonality of the contributors and the participants who are also beneficiaries. There has to be a complete identity between the contributors and the participants. Therefore, it follows, that any surplus in the common fund shall not constitute income but will only be an increase in the common fund meant to meet sudden eventualities