What is the primary interpretive difficulty in “The Qurʾān is easy, waḥy is harder”?

Al-Ḥārith al-Aʿwar: Narrator Criticism, Variant Reports and Evidence

• Determining the case of “hayyin” alone resolves the historical question
• The primary issue is whether ʿAlqamah’s reading period has an interrupted chain
• What waḥy meant in that setting
• The mere existence of a second chain determines the expression’s meaning