Q: I am a teacher and I have some Shi`ah (Shi'ites) colleagues; how should I deal with them?
A: You have to advise them, guide them to goodness, and inform them that making accusations against the Sahabah (Companions of the Prophet) is not permissible. You have to tell them that it is Wajib (obligatory) on every Muslim to love 'Aly and ask Allah to be pleased with him but without revering him excessively. It is not permissible to claim that `Aly (may Allah be pleased with him) knows the Ghayb (the Unseen), that Du`a' (supplication) may be made to Him along with Allah, or that his help may be sought. The same applies to Al-Hasan and Al-Husayn and Ja`far Al-Sadiq as well as all other Sahabah and Salaf (righteous predecessors). However, if your Shi`ah colleagues persist in Bid`ah (innovation in religion); you have to abandon them. In such case, you have neither to greet them nor to answer their greeting.
On the other hand, if they do not disclose their Bid`ah (innovation in religion) and show that they comply with your advice; you have to give them the same treatment of the hypocrites as the Prophet (peace be upon him) used to deal with the latter in Madinah. Whoever manifests their abidance by Islam and abstains from evil are treated as Muslims and their inward beliefs are to be judged by Allah.