Bismillaah Al-Hamdulillaah wa salatu wa salaamu 'ala rasulullaah Amma ba'd
Student of knowledge Abu Hasan Malik asked Shaikh Muhammad bin Hadee al-Madkhalee (hafidhahullaah) about putting these students who are just coming back (from studying) forward to teach, and Shaikh Muhammad bin Hadee al-Madkhalee said:
Do not put them forward to teach the people until you know them Tamaman (completely), because if you put them forward you are then giving them tazkiyah.
Abu Hasan (hafidhahullaah) then added:
Prevention is easier than cure.
Subhanak Allaahuma wa bihamdika ash-hadu anlaa illaaha illa anta astaghfiruka wa atubu ilayk
If I said anything correct, then it is from Allaah (subhanahu wa taa'ala), and if I erred, then that is from me and shaytan.