"But if the approach which seems to us peshuto shel mikra contradicts and opposes the received derashah which is transmitted to us by Chazal, such that it is impossible that both can be correct, for the contradictory is precluded, then it is incumbent upon us to go in the way of derash, and to translate the text according to it, because we only have the traditions of our Sages z"l, and in their light we can see light."
Hint: the above is a translation.
Update: these words are from Moses Mendelssohn's introduction to the Biur. Thanks for guessing, guys. :)