Lactantius — Divine Institutes 6.12

This is that perfect justice which protects human society, concerning which philosophers speak. This is the chief and truest advantage of riches; not to use wealth for the particular pleasure of an individual, but for the welfare of many; not for one's own immediate enjoyment, but for justice , which alone does not perish. We must therefore by all means keep in mind , that the hope of receiving in return must be altogether absent from the duty of showing mercy: for the reward of this work and duty must be expected from God alone; for if you should expect it from man, then that will not be kindness, but the lending of a benefit at interest; nor can he seem to have deserved well who affords that which he does, not to another, but to himself.

And yet the matter comes to this, that whatever a man has bestowed upon another, hoping for no advantage from him, he really bestows upon himself, for he will receive a reward from God . God has also enjoined, that if at any time we make a feast, we should invite to the entertainment those who cannot invite us in return, and thus make us a recompense, so that no action of our life should be without the exercise of mercy. Nor, however, let any one think that he is debarred from intercourse with his friends or kindness with his neighbours. But God has made known to us what is our true and just work: we ought thus to live with our neighbours, provided that we know that the one manner of living relates to man , the other to God .

Therefore hospitality is a principal virtue , as the philosophers also say; but they turn it aside from true justice , and forcibly apply it to advantage. Cicero says: Hospitality was rightly praised by Theophrastus. For (as it appears to me) it is highly becoming that the houses of illustrious men should be open to illustrious guests. He has here committed the same error which he then did, when he said that we must bestow our bounty on suitable persons . For the house of a just and wise man ought not to be open to the illustrious, but to the lowly and abject. For those illustrious and powerful men cannot be in want of anything, since they are sufficiently protected and honoured by their own opulence. But nothing is to be done by a just man except that which is a benefit.

But if the benefit is returned, it is destroyed and brought to an end; for we cannot possess in its completeness that for which a price has been paid to us. Therefore the principle of justice is employed about those benefits which have remained safe and uncorrupted; but they cannot thus remain by any other means than if they are be stowed upon those men who can in no way profit us. But in receiving illustrious men, he looked to nothing else but utility; nor did the ingenious man conceal what advantage he hoped from it. For he says that he who does that will become powerful among foreigners by the favour of the leading men, whom he will have bound to himself by the right of hospitality and friendship. O by how many arguments might the inconsistency of Cicero be proved , if this were my object!