21 (On setting up common funds and establishing a system of social assistance for priests.) We should always keep before our eyes the example of the faithful of the early Church in Jerusalem, who "held all things in common" (Acts 4;32) "and distribution was made to each according to each one's need" (Acts 4:35). So it is supremely fitting, at least in regions where the support of the clergy completely or largely depends on the offerings of the faithful, that their offerings for this purpose be collected by a particular diocesan institution, which the bishop administers with the help of priests and, when useful, of laymen who are expert in financial matters. Further it is hoped that insofar as is possible in individual dioceses or regions there be established a common fund enabling bishops to satisfy obligations to other deserving persons and meet the needs of various dioceses. This would also enable wealthier dioceses to help the poorer, that the need of the latter might be supplemented by the abundance of the former. These common funds, even though they should be principally made up of the offerings of the faithful, also should be provided for by other duly established sources. Moreover, in nations where social security for the clergy is not yet aptly established, let the episcopal conferences see to it that-in accord with ecclesiastical and civil laws-there may be either diocesan institutes, whether federated with one another or established for various dioceses together, or territorial associations, which under the vigilance of the hierarchy would make sufficient and suitable provision for a program of preventive medicine, and the necessary support of priests who suffer from sickness, invalid conditions or old age. Let priests share in this established institute, prompted by a spirit of solidarity with their brothers to take part in their tribulations while at the same time being freed from an anxious concern for their own future so that they can cultivate evangelical poverty more readily and give themselves fully to the salvation of souls. Let those in charge of this act to bring together the institutes of various nations in order that their strength he more firmly achieved and more broadly based.
Source: Presbyterorum Ordinis (Vatican.va)