If a recognized scholar who is knowledgeable of the reasons of Jarh & Ta'deel (criticism & praise) & knowledgeable of the differences found in these matters criticizes [an individual] and no one opposes this criticism then it should be accepted - may Allah bless you all. However, if a recognized scholar, similar to [the first one], opposes this criticism with a Tazkiyah (statement of praise) then the criticizer should be asked to present his proofs, the proofs of why his criticism is valid and what are the reasons behind it; so should he present the evidences, then in that case, even if a hundred scholars from among the major scholars & those most prominent among them oppose him [the criticizer] then their opposition carries no weight, as they are opposing the evidences and proofs, and opposing without evidence & proof. And Allah says:
Say: Bring forth your proof if you were indeed truthful.
So the evidence will silence thousands who have no proof with them, even should they be scholars. So these are principles that should be known, and it is upon to return back to the books of the sciences of hadith, especially the large ones [advanced ones] among them such as: Tadreebur-Rawee (Training the Narrator,) and like Fathul-Mugheeth (The Aid [victory] of The Savior) the explanantion of the 1000 verse poem [on the sciences of hadith] of Al-'Iraqi by Al-Sakhawee. These are fundamental basics for the people of knowledge. Debating and arguing in these matters with falsehood is impermissible, as that makes us from those ruin the scholarly sciences of Islam, and the principles of knowledge, and, and, etc with the like of these manners. Thus it is impermissible for a Muslim to present to the people anything but the truth, anything but the truth. And he should be far removed from trickery and deception - may Allah bless you all.