Moreover, in the reception of strangers, and the care of the sick, consider how great an expenditure of money is needed, and how much exactness and discernment on the part of those who preside over these matters. For it is often necessary that this expenditure should be even larger than that of which I spoke just now, and that he who presides over it should combine prudence and wisdom with skill in the art of supply, so as to dispose the affluent to be emulous and ungrudging in their gifts, lest while providing for the relief of the sick, he should vex the souls of those who supply their wants. But earnestness and zeal need to be displayed here in a far higher degree; for the sick are difficult creatures to please, and prone to languor; and unless great accuracy and care are used, even a slight oversight is enough to do the patient great mischief.
Source: On the Priesthood (New Advent)