All men, rich and poor, must aid one another materially and personally. The rules vary in detail, but they all maintain the principle of universal mutual aid in the Muslim fraternity. This fraternity is absolute, and it comprises men of all colours and all races... all are the sons of Adam in the flesh and all carry in them spark of the Divine Light. Everyone should strive his best to see that this spark be not extinguished but rather developed to that full "Companionship-on-High" which was the vision expressed in the last words of the Prophet [Muhammad] on his deathbed, the vision of that blessed state which he saw clearly awaiting him.

Memoirs of Aga Khan: World Enough & Time (1954)