Section — Wouters, Manual of Moral Theology
§ X. On Mandate and the Management of Affairs
I. Notion of mandate. Mandate is a contract by which someone entrusts to another some affair to be managed in his, that is, the mandator's, name, and the other, the mandatary, undertakes to manage it in that way. A general and a special mandate are distinguished, according as the mandator commits all affairs or only one affair or several affairs to the mandatary.
II. Form of mandate. With attention paid to natural law, it can be entered into both orally and in writing; but civil law should be inspected.
III. Obligations of the mandator. The mandator is bound: 1° to fulfill the obligations which the mandatary undertook within the limits of the mandate; those which he undertook by exceeding the limits of the mandate do not bind the mandator, unless he has expressly or tacitly ratified them; 2° to compensate the mandatary for the expenses to be made by him, and likewise the damages which he has suffered inculpably in executing the mandate; 3° to pay the agreed wage.
IV. Obligations of the mandatary. The mandatary is bound: 1° to execute the mandates diligently; 2° to keep himself within the limits of the mandate; otherwise he acts in his own name, and therefore does not oblige the mandator toward the third party. To what extent he can retain the excess of price, if he sells above the price assigned by the mandator or buys below it, see n. 902.
V. Cessation of mandate. Mandate ceases: 1° by legitimate revocation of the mandator, intimated to the mandatary; 2° by legitimate renunciation of the mandatary, intimated to the mandator; 3° by the affair for which the contract was entered into having been finished; 4° by the death of the mandator or of the mandatary. Some indeed teach, or hold as probable, that a mandate of donating does not expire by the death of the donor, so that the mandatary can execute the mandate of donating even after the death of the donor; but it is not clear by what reason a donation of some thing could be made in the name of a person already deprived by death of every right to the thing to be donated.
VI. Management of affairs is had when someone without mandate of the owner undertakes to manage another's affair.
Question 1. Does the manager of affairs have a right to a wage?
Response. It must be denied if he had the intention of rendering the service gratuitously. Otherwise it is disputed. Some deny it, because that right cannot arise except from a contract with the owner. But with St. Alphonsus (III, 825, at the end) and others, it seems that it must be affirmed in the case in which the owner wanted, for example, to buy something. The reason is that one who wishes, for example, to buy something also wills the normal conditions necessary for the purchase. But a normal condition is that he wishes the thing to be bought by another if he himself cannot buy it. This being posited, there is a contract, implicit on the part of the owner, between the owner and the manager of the affair, who buys the thing and receives a right to a wage.
Question 2. Is the owner bound to ratify the things which the manager of affairs prudently managed?
Response. It must be affirmed insofar as, according to the things just explained, a contract had place between him and the manager of affairs.
Note. What civil law establishes regarding the management of affairs, see in the code of one's country.