As difference in degree of capacity exists ..

 "As difference in degree of capacity exists among human souls, as difference in capability is found, therefore, individualities will differ one from another. But in reality this is a reason for unity and not for discord and enmity.
If the flowers of a garden were all of one color, the effect would be monotonous to the eye; but if the colors are variegated, it is most pleasing and wonderful. The difference in adornment of color and capacity of reflection among the flowers gives the garden its beauty and charm. Therefore, although we are of different individualities, different in ideas and of various fragrances, let us strive like flowers of the same divine garden to live together in harmony.
Even though each soul has its own individual perfume and color, all are reflecting the same light, all contributing fragrance to the same breeze which blows through the garden, all continuing to grow in complete harmony and accord. Become as waves of one sea, trees of one forest, growing in the utmost love, agreement and unity."

`Abdu'l-Bahá: The Promulgation of Universal Peace. P.25