Shaykh Abdul Ghani Al-Umaree said, “There is no problem in going to the mosques of the general folk (who are laymen not upon salafiyyah and they do not belong to a deviated organisation/misguided sect) from which no dawah (opposing the truth) is found.
As long as they do not gain strength by our visits to them (by using Salafi students of knowledge calling to the truth in their mosque to make people think that particular mosque is upon the sunnah while still bring Ahlu Bidah talkers to speak in their mosque).
Our dawah must be clear and they (the general folk in that mosque most not inivite Ahlu Bidah speakers to) speak before or after us and that platform (in that mosque) has to be specific for us.
However going to the mosques of Ahlus Sunnah (those mosques upon the creed and manhaj of the salaf us saalih (rigtheous predecessors)) are preferable.” Ref: Aloloomenglish.net
Shaykh Hussain Al-Hateebi said, “As long as there is no harm upon the dawah in giving lectures there, along with being upon taymuz (being distinct from the attendees and heads of that mosque, being distinct in possing, implementing and calling to the correct aqeedah and methodology amoung them) and being open and clear (with ones dawah to the truth, not hiding anything from it to please the attendees or the heads of the particular mosque) then it is okay (to give dawah in a mosque not upon the way Salafi way).” Ref: Aloloomenglish.net
Posted by Abdul Kareem Ibn Ozzie