[IDEM libro quadragesimo septimo ad Sabinum. ] §12.6.18.prQuod si ea condicione debetur, quae omnimodo exstatura est, solutum repeti non potest, licet sub alia condicione, quae an impleatur incertum est, si ante soluatur, repeti possit.
[THE SAME, On Sabinus, Book 47.] But if a debt is owed under a condition which is bound to be fulfilled in any case, what has been paid cannot be recovered; although under another condition, of which it is uncertain whether it will be fulfilled, if payment is made beforehand, it can be recovered.