"We must strive unceasingly and without rest to accomplish the development of the spiritual nature in man, and endeavor with tireless energy to advance humanity toward the nobility of its true and intended station."

"The mission of the Prophets, the revelation of the Holy Books, the manifestation of the heavenly Teachers and the purpose of divine philosophy all center in the training of the human realities so that they may become clear and pure as mirrors and reflect the light and love of the Sun of Reality. Therefore, I hope that—whether you be in the East or the West—you will strive with heart and soul in order that day by day the world of humanity may become glorified, more spiritual, more sanctified; and that the splendor of the Sun of Reality may be revealed fully in human hearts as in a mirror. This is worthy of the world of mankind. This is the true evolution and progress of humanity. This is the supreme bestowal. Otherwise, by simple development along material lines man is not perfected. At most, the physical aspect of man, his natural or material conditions, may become stabilized and improved, but he will remain deprived of the spiritual or divine bestowal. He is then like a body without a spirit, a lamp without the light, an eye without the power of vision, an ear that hears no sound, a mind incapable of perceiving, an intellect minus the power of reason.

Man has two powers; and his development, two aspects. One power is connected with the material world, and by it he is capable of material advancement. The other power is spiritual, and through its development his inner, potential nature is awakened. These powers are like two wings. Both must be developed, for flight is impossible with one wing. Praise be to God! Material advancement has been evident in the world, but there is need of spiritual advancement in like proportion. We must strive unceasingly and without rest to accomplish the development of the spiritual nature in man, and endeavor with tireless energy to advance humanity toward the nobility of its true and intended station. For the body of man is accidental; it is of no importance. The time of its disintegration will inevitably come. But the spirit of man is essential and, therefore, eternal. It is a divine bounty. It is the effulgence of the Sun of Reality and, therefore, of greater importance than the physical body."

`Abdu'l-Bahá, The Promulgation of Universal Peace, pp. 59-60 

25 April 1912
(excerpt from) Talk to Theosophical Society
Home of Mr. and Mrs. Arthur J. Parsons
1700 Eighteenth Street, NW, Washington, D.C.