[IDEM libro quadragensimo octauo ad Sabinum. ] §50.17.35.prNihil tam naturale est quam eo genere quidque dissoluere, quo colligatum est.
[THE SAME, in his forty-eighth book on Sabinus.] Nothing is so natural as to dissolve each thing by the same class of transaction by which it was bound.
ideo uerborum obligatio uerbis tollitur: nudi consensus obligatio contrario consensu dissoluitur.
Therefore, an obligation of words is extinguished by words; an obligation of bare consent is dissolved by contrary consent.