Consider the world of created beings, how varied and diverse they are in species, yet with one sole origin. All the differences that appear are those of outward form and colour. This diversity of type is apparent throughout the whole of nature.
Behold a beautiful garden full of flowers, shrubs, and trees. Each flower has a different charm, a peculiar beauty, its own delicious perfume and beautiful colour. The trees too, how varied are they in size, in growth, in foliage -- and what different fruits they bear! Yet all these flowers, shrubs and trees spring from the self-same earth, the same sun shines upon them and the same clouds give them rain.
So it is with humanity. It is made up of many races, and its peoples are of different colour, white, black, yellow, brown and red -- but they all come from the same God, and all are servants to Him.
- Abdu'l-Baha (From a talk on October 28, 1911; ‘Paris Talks: Addresses given by ‘Abdu’l-Bahá in Paris in 1911-1912’)