Bahá’u’lláh taught that the Prophet, or “Manifestation of God,” is the Light-bringer of the spiritual world, as the sun is the light-bringer of the natural world. Just as the material sun shines over the earth and causes the growth and development of material organisms, so also, through the Divine Manifestation, the Sun of Truth shines upon the world of heart and soul, and educates the thoughts, morals and characters of men. And just as the rays of the natural sun have an influence which penetrates into the darkest and shadiest corners of the world, giving warmth and life even to creatures that have never seen the sun itself, so also, the outpouring of the Holy Spirit through the Manifestation of God influences the lives of all, and inspires receptive minds even in places and among peoples where the name of the Prophet is quite unknown.
(Baha'u'llah and the New Era)