Al-Khoei of New York comments on the Amman Message of tolerance and mutual recognition among Muslim schools of thought

Religious Authority: 
Sayyid Abdul Majid al-Khoei
Fatwa Question or Essay Title: 
Are the Jafari, The Ibadhya, Zaydi, and Adhahirya schools part of Islam? And what is the ruling on declaring one of the followers of these schools or the Ashari doctrine or Sufism an apostate?

First, all the schools mentioned in the question are part of Islam. If a person believes that there is no God but God and Muhammad is his prophet and recognize the pillars of Islam, is a Muslim.

Second, it is not permissible to declare one of the followers of the groups, sects and doctrines mentioned in the question an apostate except if this follower deny one of the pillars of Islam.