God says in the glorious Qur'án: "The soil was black and dried. Then we caused the rain to descend upon it and immediately it became green, verdant, and every kind of plant sprouted up luxuriantly." In other words, He says the earth is black, but when the spring showers descend upon it that black soil is quickened, and variegated flowers are pushed forth. This means the souls of humanity belonging to the world of nature are black like unto the soil. But when the heavenly outpourings descend and the radiant effulgences appear, the hearts are resuscitated, are liberated from the darkness of nature and the flowers of divine mysteries grow and become luxuriant. Consequently man must become the cause of the illumination of the world of humanity and propagate the holy teachings revealed in the sacred books through the divine inspiration. (‘Abdu'l-Baha, Tablets of the Divine Plan)
