Is the prostration of gratitude (Sujud al-Shukr) permissible during formal prayer (Salat)?
Chapter on the Description of Prayer
Al-Mughni
Book of Prayer
Primary text
Prostration of gratitude is not permitted during formal prayer because its cause is external to the prayer itself. If a person performs it during prayer, the prayer is invalidated, unless the person was forgetful or ignorant of the prohibition.
Supporting text
If the prostration of 'Sad' (Quranic prostration) is performed during prayer, and it is not considered a mandatory prostration (Azimah), a ruling suggests it might invalidate the prayer because it is a prostration of gratitude. Alternatively, it might not invalidate the prayer because its cause relates to recitation, making it analogous to the prostration of recitation.