The pairing of the Holy Prophet and Ali was a matter of great significance, and it had deep implications and repercussions. In the various source books that have come down to us, no light is thrown on such implications. We will, therefore, have to undertake an exercise on our own account in spelling out the underlying implications. In the process of brotherhood-formation every emigrant from Makkah was paired with an Ansar of Madina. The Holy Prophet was himself an emigrant from Makkah, and the question that arises for consideration is: why did the Holy Prophet not pair himself with any Ansar of Madina ? To be paired with the Holy Prophet was a great honor, and many Ansars coveted this honor. If the Holy Prophet had shown preference for some particular Ansar that would have been a cause for jealousy on the part of the other Ansars who equally coveted the honor. In Madina the status of the Holy Prophet was that of a ruler, and if he had shown preference for some particular Ansar, that would have been a cause of heart burning for the other Ansar. The Holy Prophet did not pair himself with any Ansar because of his impartiality.
A consequence of the pairing of the emigrants and the Ansars was that the emigrants shared with the Ansar their income and property. If the Holy Prophet did not pair with any particular Ansar the question is what was the source of income of the Holy Prophet in Madina? When the Holy Prophet in order to maintain his impartially did not choose to have a share in the income and property of a particular Ansar, it implies that he had his share in the income and property of all Ansars. It is a common practice with religious fraternities that each person belonging to the fraternity contributes a certain percentage of his income to the common fund of the fraternity which is places at the disposal of the head of the fraternity. It appears that the Ansars of Madina constituted some common fund of similar nature and placed it at the disposal of the Holy Prophet. Presumably some property was also placed at the disposal of the Holy Prophet the income whereof could be utilized to meet his expenses as well as other common needs. The emigrants from Makkah were traders, and in Madina as well they undertook trading activities. Indeed Madina offered more trading opportunities than Makkah. The Holy Prophet ran some sort of business at Makkah which was managed by Ali. It appears that the same business was continued in Madinah. As the Holy Prophet had to devote a good deal of his attention to the affairs of the State, the responsibility for running the business enterprise rested a good deal on Ali. The Holy Prophet and Ali were already cousins and the brotherhood constituted signified that the ties between the Holy Prophet and Ali became still closer and stronger, and they shared each other's property.
