The Central distinguishing feature of the Bahá’í Teachings is The Oneness of Mankind. This principle applies not only to the relationships between individuals but is “…concerned primarily with the nature of those essential relationships that must bind all the states and nations as members of one human family.”
Baha’u’llah said that “All men have been created to carry forward an ever-advancing civilization”
According to the Baha’i Teachings, the Prophets and Messengers of God such as Jesus, Moses, Abraham, Buddha, Krishna, Muhammad, The Bab and Bahá’u’lláh have been sent as Teachers, and the purpose of religion is not to divide the human race but to unite us. In ancient times the highest level of human organization was the tribe …such as the original tribes of Israel or of ancient Persia or Greece. Unity at the level of the nation came later but always it has been through the influence of the Prophets that men have been able to reconcile their differences sufficiently to attain the next higher level of unity:
“Why has God sent the Prophets? It is self-evident that the Prophets are the Educators of men and the Teachers of the human race. They come to bestow universal education upon humanity, to give humanity training, to uplift the human race from the abyss of despair and desolation and to enable man to attain the apogee of advancement and glory.” –`Abdu’l-Bahá
In ancient times communication 
between the diverse peoples of the world was very slow and in some cases non-existent. But today no one can deny that the world is contracted into a neighborhood. Clearly “Love thy Neighbor” must be viewed in a new light in the age of the internet:
“Bahá’u’lláh has proclaimed the oneness of the world of humanity. He has caused various nations and divergent creeds to unite. He has declared that difference of race and color is like the variegated beauty of flowers in a garden. If you enter a garden, you will see yellow, white, blue, red flowers in profusion and beauty — each radiant within itself and although different from the others, lending its own charm to them. Racial difference in the human kingdom is similar. If all the flowers in a garden were of the same color, the effect would be monotonous and wearying to the eye.” –`Abdu’l-Bahá
But noble principles and pleasant words are meaningless if they do not find their way into action. It is clear then that new teachings are needed to bring practical modern application to profound ancient principles. So Baha’u’llah has defined the necessary relationship between these diverse peoples of the world saying that the nations of the world must make the same difficult but truly wise decision that the thirteen colonies of America made two centuries ago; the decision to form a united federation. He says that it is the duty of the Sovereigns of the World…
“…to convene an all-inclusive assembly, which either they themselves or their ministers will attend, and to enforce whatever measures are required to establish unity and concord amongst men. They must put away the weapons of war, and turn to the instruments of universal reconstruction. . Should one king rise up against another, all the other kings must arise to deter him. Arms and armaments will, then, be no more needed beyond that which is necessary to insure the internal security of their respective countries. If they attain unto this all-surpassing blessing, the people of each nation will pursue, with tranquillity and contentment, their own occupations, and the groanings and lamentations of most men would be silenced. We beseech God to aid them to do His will and pleasure.” –Bahá’u’lláh
World unity is the next stage in man’s development. We have nothing to fear and much to gain from this Divinely-ordained change; a promise enshrined in ancient texts and scriptures that will forever change the fortunes of mankind.
“The unity of the human race, as envisaged by Bahá’u’lláh, implies the establishment of a world commonwealth in which all nations, races, creeds and classes are closely and permanently united, and in which the autonomy of its state members and the personal freedom and initiative of the individuals that compose them are definitely and completely safeguarded.” –Shoghi Effendi
Baha’u’llah assures us that this new relationship between the peoples of the world will become a reality in this Great Day of God as fortold by Isaiah, the greatest of the Hebrew Prophets:
“…nation shall not lift up sword against nation, neither shall they learn war any more… …They shall not hurt nor destroy in all my holy mountain: for the earth shall be full of the knowledge of the Lord, as the waters cover the sea.” –Isaiah
The process that will bring this relationship to fruition is not a top-down process. It starts at the lowest levels of society, is reinforced and protected by divine institutions and – most importantly – every one of us can participate in it.
