الكافي- ط الاسلامية, volume 3, page 496

1. Ali ibn Ibrahim has narrated from his father from Hammad ibn ‘Isa from Hariz from Zurarah and Muhammad ibn Muslim who has said the following: “Once we both asked abu ‘Abd Allah (a.s.), about the words of Allah, most Majestic, most Glorious, in the following verse of the Holy Quran. ‘Charity funds (zakat) are only for the poor, the destitute, and the tax collectors. (It is also for the) people whose hearts are inclined (toward Islam), the slaves, those who cannot pay their debts, for the cause of Allah, and for those who have become needy on a journey. Paying zakat is an obligation that Allah has decreed. Allah is All-knowing and All-wise. ’(9:60) ‘Can all the people and cases mentioned in this verse receive zakat even though they may not believe (in Divine Authority of ’A’immah)?’ He replied, ‘The Imam gives charity to all of them; they announce their obedience to him.’ I (the narrator) then asked, ‘Even if they do not acknowledge (his Divine Authority)?’ He then said, ‘O Zurarah, were he to give charity only to those who acknowledge (his Divine Authority) and not to others, there would remain no one or cases as recipient of (zakat) charity. He gives charity to those who do not acknowledge (his divine authority) so they incline to religion to become strong (in faith). However, today you and your friends give zakat only to those who acknowledge (our Divine Authority) if you find one who believes (in our Divine Authority).’ He then said, ‘The share of those who show interest in Islam and the share of slaves to be emancipated are of general nature and other shares in a charity are for certain people but not for everyone.’ I (the narrator) then asked, ‘What happens if there is no recipient of zakat?’ He replied, ‘Allah, the Most Majestic, the Most Glorious, has not made any charity compulsory without any recipient.’ I (the narrator) then asked, ‘What happens if charity is not enough?’ He replied, ‘The amount of compulsory charity Allah has sanctioned in the properties of affluent people for the poor ones is enough. If He knew that it is not enough, He would sanction a greater amount. Shortages do not come from the amount Allah has made compulsory but it comes from non-payment. There are those who do not pay what belongs to the needy, thus, shortages are not due to the degree of Allah’s sanctioned charity for the needy. Had people paid the rights of the needy, they would have lived happy.’”

Translation: Muhammad Sarwar — attributed by Thaqalayn·The Arabic above is the original.