[IDEM libro sexto decimo ad Sabinum. ] §44.7.8.prSub hac condicione 'si uolam' nulla fit obligatio: pro non dicto enim est, quod dare nisi uelis cogi non possis: nam nec heres promissoris eius, qui numquam dare uoluerit, tenetur, quia haec condicio in ipsum promissorem numquam exstitit.
[THE SAME, from the sixteenth book on Sabinus.] Under this condition 'if I wish', no obligation arises; for that which you cannot be compelled to perform unless you wish is regarded as not having been said; for neither is the heir of that promisor bound who never wished to perform, because this condition was never fulfilled in the person of the promisor himself.