What is the ruling if someone makes speech after finishing prayer believing it was complete, concerning an omission?
Chapter on the Two Prostrations of Forgetfulness
Al-Mughni
Book of Prayer
Primary text
Regarding one who concludes the prayer with an omission, believing it to be complete, and then speaks, there are three narrations. The first states the prayer is not invalidated if the speech concerns the prayer's matter, similar to the speech in the Hadith of Dhu al-Yadayn, because the Prophet and his Companions spoke and then continued their prayer, and the Prophet is an excellent exemplar. The second narration states the prayer is invalidated, which is the view of Al-Khallal and his companion, and the doctrine of the Ashab ar-Ra'y, due to the generality of the prohibition Hadiths.
Supporting text
The third narration distinguishes: the Imam's prayer is not invalidated because the Prophet (who was an Imam) spoke and continued. However, the prayer of the followers who spoke is invalidated because their following of Abu Bakr and 'Umar when they spoke in response to the Prophet is not sound, as their response was obligatory. Similarly, following Dhu al-Yadayn is invalid as he spoke questioning an omission at a time when it was permissible, a situation not present in our time. This third view is chosen by Al-Kharqi, and it is specific to speech concerning the prayer's matter because the Prophet and his Companions only spoke about the prayer, thus the permissibility of speech is restricted to where the text specifies due to necessity, and analogy to other matters is forbidden.