Quran's Tafhim ( explanation)
*16) This implies those people who at `that time had been expelled from Makkah and other parts of Arabia only because they had embraced Islam. Before the conquest of the territory of the Ban; an-Nadir these emigrants had no permanent means of sustenance. Therefore. it was commanded that in the properties which were then taken, and in the fai properties which are taken in future there is also a share of these people along with the common poor people and the orphans and the wayfarers. With these properties all such people should be helped, who are forced to emigrate for the cause of AIlah and His Messenger to the abode of Islam. Accordingly, the Holy Prophet (upon whom be Allah's peace) distributed a part of the properties taken from the Bani an-Nadir among the Emigrants and the oases which the Ansar had set aside for the support and maintenance of their emigrant brothers were returned to them. But it is not correct to think that the Emigrants had this share in the fai only at that time. In fact, the intention of the verse is to point out that till Resurrection it is the duty of the Islamic government of the country to settle the people who are exiled and compelled to take refuge in it because of being Muslims and to enable them to stand on their feet economically; and it should spend on this head also from the fai properties besides the zakat funds.