Ad Dig. 3,5,38ROHGE, Bd. 4 (1872), S. 217: Liberation eines Schuldners ohne dessen Wissen durch Zahlung bez. Angabe an Zahlungsstatt, Novation eines Dritten.Gaius, On Verbal Obligations, Book III. Where anyone pays a debt for another, even though the latter is unwilling, or ignorant of the fact, he discharges him from liability; but where money is owing to anyone, another cannot legally exact it without the consent of the former; for both natural reason and the law have established the rule that we may improve the condition of a man who is ignorant and unwilling, but we cannot make it worse.

The Same, On Oral Obligations, Book III. If only one of two joint-stipulator s institutes legal proceedings at a time, the promisor will not be released by tendering money to the other.

Gaius, On Oral Obligations, Book III. If a slave stipulates for his master, or for his usufructuary, with reference to property belonging to his master, Julianus says that he acquires the obligation for the benefit of his master, and that the usufructuary can be paid just as anyone who has been joined. 1If a slave owned in common should stipulate with reference to property belonging to one of his masters, the better opinion is that the stipulation is acquired for both of them; but he whose property was made use of in making the stipulation can properly avail himself of an action in partition, or the action on partnership, in order to recover his share. The same rule applies, if a slave acquires for one of his masters by means of his labor. 2If each one of his two masters stipulates that the same ten aurei shall be given to a slave, jointly owned by them, and but one answer was made, there will be two joint stipulators, as it is established that a master can stipulate for payment to his slave. 3Just as a slave acquires for one of his masters alone, if he stipulates for him by name, so it is decided that if he purchases property in the name of one of his masters, he will acquire it for him alone. In like manner, if he lends money to be paid to one of his masters, or transacts any other business whatever, he can expressly provide that the property shall be restored, or payment be made to one of them alone. 4The question arose whether a slave forming part of an estate can stipulate for the benefit of the future heir. Proculus says that he cannot, because at that time he was a stranger. Cassius is of the opinion that he can, as he who afterwards becomes the heir is held to have succeeded to the deceased at the time of his death. This reason is supported by the fact that the entire body of slaves is understood to represent the deceased at the time of his death, although the heir may not appear for some time. Hence it is clear that the benefit of the slave’s stipulation is acquired for the heir.

Gaius, On Oral Obligations, Book III. If a surety should bind himself under the condition that a ship will arrive from Asia, and I accept him with the understanding that the obligation will only render him liable during his lifetime, and while the condition is pending he receives a release from me, and the surety dies before the condition is fulfilled, I can immediately bring suit against the principal debtor, because even if the condition should be fulfilled, it could never establish an obligation against one who is already dead, and could not confirm the release which I had granted.

Gaius, On Oral Obligations, Book III. It cannot be doubted that a son under paternal control or a slave who is permitted to manage his own peculium has also the right to make the debts of the peculium the subject of novation, if the parties stipulate; and this is by all means the case if his condition will be improved by doing so. For if he directs a third party to stipulate, it makes a difference whether this is done with the intention of making a donation, or in order that he may transact the business of the son or the slave, and on this ground the action on mandate with reference to the peculium is acquired by them. 1There is no doubt whatever that the relative of an insane person, or the curator of a spendthrift, has the right of novation, if this is to the advantage of the said insane person or spendthrift. 2In a word, we should remember that there is nothing to prevent the novation of several obligations by one agreement, as for instance, if we stipulate as follows, “Do you promise to pay what Titius and Seius are obliged to pay me?” for although they are liable for different reasons, still both are released by the right of novation, as the liability of both is united in the person of him with whom we now stipulate.

Gaius, On Oral Obligations, Book III. A slave cannot give a release by the order of his master.