Tabarra - disassociating from Ahl al-Bayt enemies , is a part of the Shia Branches of Religion and means the obligation of disassociating from the enemies of God, Muhammad and the Ahl al-Bayt. It does not mean an obligation to hate such a person.
The doctrine of Tabarra itself does not dictate whom to disassociate from or whom to associate with. It dictates the disassociation of those indentified as enemies of Ahl al-bayt. The identification is up to every individual.
For example, some people may regard Umar as the enemy of Ahl al-Bayt. In that case, it becomes obligatory to disassociate oneself from Umar. However, others may regard Umar to be a friend and lover of Ahl al-Bayt, and for them the opposite comes obilgatory in accordance to Tawalla.
Although Tabarra specificaly means to disassociate from enemies of God, it contains by effect the obligation to disassociate from evil acts and fobidden things, for example seeing someones awrah.
A Qur'anic verse can be found that carries the same message as this doctrine. By Arberry, verse 9:1:
Baraatun is derived from the same consonantal root as Tabarra.
Since Shias and Sunnis have different sources of hadith, they tend to come to different conclusions regarding whom the enemies of Ahl al-Bayt are.
In some cases Sunni and Shia have the same view, for example regarding Abu Lahab, Abu Jahl and Umayah ibn Khalaf. But controverses arise concerning Sahabas since Sunnis believe in the Uprightness of all Sahaba while Shia do not.
Due to the Shia view of early Muslim history, one Shia scholar stated:
Note that the scholar says "from their enemies" and not "from Umar & co". Every Muslim believes that it is important to disassociate themselves from the enemies of Muhammad, however Muslims differ upon who those are.
Shia also believe that this view was held by the descendants of Muhammad. Shia hold for authentic a narration attributed to Muhammad al Baqir. He was reported to have replied to his disciple who had sought the Imam's opinion regarding Abu Bakr and Umar:
In the same book, on the same page appears the following:
Since Shia hold for authentic narrations where the desendants of Muhammad cursed the Sunni Caliphs, Shia also curse them when doing tabarra.
This added to the persecution of the Shias by the Sunnis. To protect themself in times where their life where in jeopardy, Shias used the doctrine of Taqiyya and where prevented from using tabarra in public.
Even though Tabarra is not a part of the Sunni aqidah, they have been known to use it in some occansions, for example to cursed upon Ubaid-Allah ibn Ziyad, a person they hold as responsible for the killing of Husain ibn Ali in the Battle of Karbala:
In countries where Shias are in a minority they continue to perform Taqiyya. For example, Saudi Arabia, Southern Afghanistan, Parts of Pakistan, Sunni areas of Iraq and in parts of Jordan.
Doing tabarra still causes Sunnis to feel dislike when confronted with the prayers. Due to some hadith attributed to the Shia Imams, some Shia scholars have argued that it is not permissible to pray for divine curse upon Sahaba in front of Sunnis, since that would hurt their feelings and the strive for unity among Muslims.