The ruling on lying against innovators
Shaykhul-Islaam Ibn Taimiyyah رحمه الله said: “lying against an individual is completely forbidden, regardless if he is a Muslim or a disbeliever or a transgressor. However fabricating a lie against the believer is severer. In spite of all forms of lying on someone being forbidden, it is permissible to resort to Ma’aareedh (speech that has an apparent meaning that can be different than the intended meaning) during times of legitimate necessity” .
Shaykh Rabee’ bin Haadee Al-Madkhalee حفظه الله تعالى was asked:
Is it permissible to lie against people of innovations and other people of misguidance?
And he replied:
“It is impermissible to lie against disbelievers or innovators or anyone. We clarify their misguidance, we quote it literally from their books or other sources then we discuss it scholastically, that is what we do.
And we ask Allaah to guide the Salafis to truthfulness and justness in statements and actions, we see it absolutely impermissible for a Muslim to fabricate a lie against a Muslim or a disbeliever, and we seek refuge in Allaah” .
And Allaah knows best.
 Majmoo’ur-rasaa’il wal masaa’il 5/105 via http://www.rabee.net/show_book.aspx?id=311&pid=1&bid=15.
 tape (fearing Allaah and truthfulness).