Martin Luther - To adhere to the simple, pure, and natural meaning of the words in Scripture

But let our sentiment rather be this: that neither conclusion nor trope is to be admitted into the Scriptures, unless the evident strife of the particulars, or the absurdity of any particular as militating against an article of faith, require it: but, that the simple, pure, and natural meaning of the words is to be adhered to, which is according to the rules of grammar, and to that common use of speech which God has given unto men. For if every one be allowed, according to his own lust, to invent conclusions and tropes in the Scriptures, what will the whole Scripture together be, but a reed shaken with the wind, or a kind of Vertumnus? Then, in truth, nothing could, to a certainty, be determined on or proved concerning any one article of faith, which you might not subject to cavillation by means of some trope. But every trope ought to be avoided as the most deadly poison, which is not absolutely required by the Scriptures itself. 


- Martin Luther (The Bondage of the Will, Section 77)