[IDEM libro quarto ex Minicio. ] §17.1.33.prRogatus ut fideiuberet si in minorem summam se obligauit, recte tenetur: si in maiorem, Iulianus uerius putat quod a plerisque responsum est eum, qui maiorem summam quam rogatus erat fideiussisset, hactenus mandati actionem habere, quatenus rogatus esset, quia id fecisset, quod mandatum ei est: nam usque ad eam summam, in quam rogatus erat, fidem eius spectasse uidetur qui rogauit.
[THE SAME in the fourth book of his Epitome of Minicius.] If a person who has been asked to act as a guarantor binds himself for a smaller sum, he is rightly held liable. If he does so for a larger sum, Julian thinks that the opinion given by most authorities is more correct, namely, that he who has guaranteed a larger sum than he was asked to do has an action of mandate only to the extent that he was asked; because he has performed what was commissioned to him: for he who made the request seems to have relied on the other's credit up to the sum for which he was asked.