6 Conditions relating to past or present time either make the obligation void at once, or have no suspensive operation whatever. Thus, in the stipulation 'Do you promise to give so and so, if Titius has been consul, or if Maevius is alive?' the promise is void, if the condition is not satisfied; while if it is, it is binding at once: for events which in themselves are certain do not suspend the binding force of an obligation, however uncertain we ourselves may be about them.
7 The performance or nonperformance of an act may be the object of a stipulation no less than the delivery of property, though where this is the case, it will be best to connect the nonperformance of the act to be performed, or the performance of the act to be omitted, with a pecuniary penalty to be paid in default, lest there be doubt as to the value of the act or omission, which will make it necessary for the plaintiff to prove to what damages he is entitled. Thus, if it be a performance which is stipulated for, some such penalty should be added as in the following: 'If so and so is not done, do you promise to pay ten aurei as a penalty?' And if the performance of some acts, and the nonperformance of others, are bargained for in the same stipulation, a clause of the following kind should be added, 'If any default is made, either as contrary to what is agreed upon, or by way of nonperformance, do you promise to pay a penalty of ten aurei?'
TITLE XVI. OF STIPULATIONS IN WHICH THERE ARE TWO CREDITORS OR TWO
DEBTORS
There may be two or more parties on either side in a stipulation, that is to say, as promisors or promisees. Joint promises are so constituted by the promisor answering, 'I promise,' after they have all first asked the question; for instance, if after two promises have separately stipulated from him, he answers, 'I promise to give so and so to each of you.' But if he first promises to Titius, and then, on another's putting the question to him, promises to him too, there will be two distinct obligations, namely, one between him and each of the promisees, and they are not considered joint promisees at all. The usual form to constitute two or more joint promisors is as follows,—'Maevius, do you promise to give five aurei? Seius, do you promise to give the same five aurei?' and in answer they reply separately, 'I promise.'
1 In obligations of this kind each joint promisee is owed the whole sum, and the whole sum can be claimed from each joint promisor; and yet in both cases but one payment is due, so that if one joint promisee receives the debt, or one joint promisor pays it, the obligation is thereby extinguished for all, and all are thereby released from it.
2 Of two joint promisors one may be bound absolutely, while performance by the other is postponed to a future day, or made to depend on a condition; but such postponement or such condition in no way prevents the stipulator from at once suing the one who was bound absolutely.