What are the specific characteristics related to the mandatory components of prayer?
Chapter on what invalidates the prayer if omitted intentionally or forgetfully
Al-Mughni
Book of Prayer
Primary text
The opening takbir (Takbirat al-Ihram) is unique in that prayer cannot commence without it, based on the hadith stating, 'Its prohibition is the takbir.' Standing (Qiyam) is unique in that it is waived in supererogatory (nafl) prayers due to the difficulty in prolonging them excessively. Recitation of Al-Fatiha is unique in that it is waived for the follower (Ma'mum), as the Imam's recitation suffices for them. The final salutation (Salam) is unique in that if forgotten, one only needs to perform it without further action to rectify the omission.
Supporting text
Some scholars include the intention to exit the prayer within the salutation and the second salutation as obligatory acts, though this view is contradicted by the omission of these acts from the list of obligations by Al-Khiraqi.