Because of his teaching of the Fatiha

قيل عن أبي منصور الخياط

قال السمعاني : رئي بعد موته ، فقال : غفر الله لي بتعليمي الصبيان الفاتحة

سير أعلام النبلاء

Abu Mansoor al-Khayyat (rahimahullah) was seen in a dream after his death. (He was asked, “What did Allah do to you?”)

He replied, “He forgave me, due to me teaching children Surah al-Fatiha”

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