Another principle strongly emphasized by ‘Abdu’l-Bahá is the establishment of an international auxiliary language.

As the nervous system is one through out the body, and co-ordinates all the organs and limbs, so the body of humanity requires one universal language and writing to be learned by all people in addition to the mother tongue, which shall serve to interpret its needs, unite its interests and consolidate its purposes; and diversity of tongues engenders the paralysis of the body of mankind. Those who have concern for human welfare and progress will surely give this subject the attention it deserves.

But the principle by which ‘Abdu’l-Bahá is most widely known, and for which He has been most extensively quoted, is that of universal peace. The assurance that this is the century of universal peace, the age of the elimination of warfare, the day of the most mighty surging of the spiritual waves and the full illumination of the Sun of Righteousness—this assurance is ‘Abdu’l-Bahá’s steadfast covenant with those who follow Him.

Today the disaster of warfare is a net thrown over the whole of humanity, like the net thrown over a gladiator about to be slain. None can emerge from this net until all emerge. But the very fact that there is no escape for one save through escape for all, and the overwhelming danger of the present situation, brings the consciousness of the oneness of humanity nearer day by day. Therefore this overshadowing calamity feared as a net of death by those who view it with personal eyes, yet is seen to be a garment of divine protection by those who view all things in their spiritual light.

For the effort to avoid universal warfare is binding the minds and hearts of those who have been divided during history’s ten thousand years. It is creating the great agencies and institutions of the future humanity; it is destroying all agencies and institutions whose purpose is to keep humanity divided and enslaved. Consider how the world's two most powerful kings have lately been overthrown and their empires rent asunder, and the full toll of inveterate ambition and greed has not yet been taken.

Therefore the indifferent are becoming mindful, and the activities of all humanitarians are finding a common channel and a unified expression. But peace, perfect peace, must first possess the heart, through the breaths of the Holy Spirit; consequently those among the humanitarians who are wisest, while they strive to produce concrete results and discuss all possible methods, nevertheless have for their great objective the reconciling of the hearts of men. For only that which is established in the heart can ever be established in the world, and peace will never be made real, lasting or secure, until the world has recognized the power of the Holy Spirit which alone can conquer and subdue the rebellious hearts or ingraft one changeless ideal in the restless, ever-divided minds. This is the Most Great Peace; this is the Peace of God.

The arch which these social principles of ‘Abdu’l-Bahá, like pillars, are intended to support—the structure which fulfills their purpose and directs their use—is the principle of an international tribunal.