Today, if we want to achieve a consensus on common ethical principles that serve to solve the problems of moral corruption that affect all levels of society, it is necessary to take into account the ethical teachings of religions.
Nations are increasingly losing the cultural and religious homogeneity they once preserved and are becoming a mosaic of ethnic and cultural minorities with different religious beliefs. This plural and multicultural reality of many democratic societies today requires a mutual understanding between different moral conceptions in order for us to live in peace and try to solve human and social problems together.
The Age of “One Global Family”
As Dr Sun Myung Moon explains in this quote, humanity is now entering the age of “One Global Family.” The world is made up of a mosaic of nations with ethnic, cultural and different religions that in the past lived isolated from one another, but today are forced to understand each other, to live in peace and to cooperate.
We are entering the age of “One Global Family,” in which we will have no choice but to live in much closer proximity to those whose religions, nationalities, and skin colors are different from our own.
In such a world, we will need to develop a genuine acceptance for — as opposed to a simple appreciation of — the wide variety of religions, cultural traditions and lifestyles around us. It will be impossible for any individual or group to selfishly choose to possess their own separate haven.
No world peace without religious peace!
After the end of the ideological conflicts between democracy and communism, new conflicts and tensions of an ethnic and religious character have resurfaced and proliferated on a worldwide scale, especially the serious problem of Islamic terrorism. For this reason, understanding and peace among religions is vital to world peace, as Hans Küng enthusiastically states.
All the religions of the world must recognize their responsibility for world peace. That is why I will not tire of reiterating a thesis for which I have seen a growing sympathy throughout the world: There can be no peace between nations without peace between religions or, more briefly: No world peace without religious peace! 
We are all brothers and sisters of the same one great family
Dr Sun Myung Moon abounds in this statement by emphasizing the imperative need for interreligious harmony to achieve world peace.
The essence of my teaching is that interreligious harmony is a necessary condition for world peace. No single religion has manifested God completely. Therefore, diversity and differences of religion have been inevitable.
Yet, as many great religious leaders have taught, because we are all children of the same Heavenly Parent, we are all brothers and sisters of the same one great family, and interreligious conflict and divisive hatred are unnecessary. 
 Sun Myung Moon, Absolute Values and the Reassessment of the Contemporary World, International Conference on the Unity of the Sciences, Founder's Address, August 24, 1991.
 H. Küng, Proyecto de una ética mundial, Trotta, Madrid, 1991, p. 98.
 Sun Myung Moon, Let Us Bring Religious Harmony for the Sake of World Peace, Lotte Hotel, Seoul, Korea, The Fourth Conference on “God: The Contemporary Discussion” and The Third Youth Seminar on World Religions, August 14, 1984.