Fostering world citizenship is a practical strategy for promoting sustainable development. So long as disunity, antagonism and provincialism characterize the social, political and economic relations within and among nations, a global, sustainable pattern of development can not be established. Over a century ago Bahá’u’lláh warned, "The well-being of mankind, its peace and security, are unattainable unless and until its unity is firmly established." Only upon a foundation of genuine unity, harmony and understanding among the diverse peoples and nations of the world, can a sustainable global society be erected.