[PAULUS libro uicensimo nono ad edictum. ] §13.5.8.prSi uero mihi aut Titio constitueris te soluturum, mihi competit actio: quod si, posteaquam soli mihi te soluturum constituisti, solueris Titio, nihilo minus mihi teneberis.
[PAULUS, from the twenty-ninth book on the Edict.] If, however, you have informally promised that you will pay to me or to Titius, the action belongs to me; but if, after you informally promised that you would pay to me alone, you pay to Titius, you will nonetheless remain liable to me.