Today the world of humanity is in need of ...

Today the world of humanity is in need of international unity and conciliation. To establish these great fundamental principles a propelling power is needed. It is self-evident that the unity of the human world and the Most Great Peace cannot be accomplished through material means. They cannot be established through political power, for the political interests of nations are various and the policies of peoples are divergent and conflicting. They cannot be founded through racial or patriotic power, for these are human powers, selfish and weak. The very nature of racial differences and patriotic prejudices prevents the realization of this unity and agreement. Therefore, it is evidenced that the promotion of the oneness of the kingdom of humanity, which is the essence of the teachings of all the Manifestations of God, is impossible except through the divine power and breaths of the Holy Spirit. Other powers are too weak and are incapable of accomplishing this. 
For man two wings are necessary. One wing is physical power and material civilization; the other is spiritual power and divine civilization. With one wing only, flight is impossible. Two wings are essential. Therefore, no matter how much material civilization advances, it cannot attain to perfection except through the uplift of spiritual civilization. 

 `Abdu'l-BaháThe Promulgation of Universal Peace