Is it permissible to consider Islamic schools that are not Sunni part of true Islam?

Religious Authority: 
Shaykh Said Abd al-Hafiz al-Hijjawi
Fatwa Question or Essay Title: 
Is it permissible to consider Islamic schools that are not Sunni part of true Islam?

No Muslim may declare another Muslim (whoever has pronounced the two declarations of faith [There is no got but God and Muhammad is his Prophet] and who prays toward the qibla [the direction of Mecca]) an apostate. Any of the followers of the four Sunni schools of jurisprudence, as well as the Zahiri school, the [Shia] Jafari school, the [Shia] Zaidi school, and the [Shia] Ibadi school is considered a Muslim.

[The above is excerpted from longer article; please see the attached file for the original Arabic. Only one out of ten pages has been attached. The remainder may be found on the website.]

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