The “double task of simultaneously building an ideal society and perfecting the behavior of individuals” – the “course set forth by Bahá'u'lláh”

At the very core of the aims of the Faith are the establishment of justice and unity in the world, the removal of prejudice and enmity from among all people, the awakening of compassion and understanding in the hearts of all men and women, and the raising of all souls to a new level of spirituality and behavior through the vitalizing influence of divine Revelation. The course set forth by Bahá'u'lláh for the attainment of these aims is the double task of simultaneously building an ideal society and perfecting the behavior of individuals. For this dual and reciprocal transformation He has not only revealed laws, principles and truths attuned to the needs of this age, but has established the very nucleus and patter of those institutions which are to evolve into the structure of the divinely purposed world society. 
(From a letter dated 2 July 1996 written on behalf of the Universal House of Justice to an individual believer)