Shaikhul Islaam Ibn Taymiyyah (rahimahullaah) said:

”Refutation against the people of falsehood cannot be comprehensive except when it is in agreement with the (Authentic) Sunnah from every angle.  And if not, the one who conforms to the (Authentic) Sunnah in a particular angle and opposes it from another angle, then those arguing against him will strive (to gain something) from that angle in which he opposed the (authentic) Sunnah, and they will use it as evidence to prove what is in agreement with what they are upon (of falsehood) from those arguments that are in opposition to the (authentic) Sunnah.”  [Source:6/210- درء تعارض العقل والنقل 211]