Building unity in diversity is not easy. It requires a conscious effort from a large number of people. Bahá'u'lláh compared the world of humanity with the human body. Within this organism, millions of cells, diverse in form and function, play their role in maintaining a healthy system. The principle that governs its operation is cooperation. Its various parts do not compete for resources; rather, each cell is linked to a continuous process of giving and receiving. All human beings are members of the body of humanity. Each one is essentially noble, has a unique soul. They all have the common purpose of carrying forward a constantly advancing material and spiritual civilization.