There are three narrations regarding it: The first is that the prayer is not invalidated if the speech concerns the state of the prayer, such as the speech of the Prophet (peace be upon him) and his companions in the hadith of Dhu al-Yadayn, because the Prophet (peace be upon him) and his companions spoke and then built upon their prayer, and we have in the Messenger of Allah an excellent example. The second is that their prayer is invalidated, which is the opinion of al-Khallal and his companion, and the school of the People of Opinion (Ashab al-Ra'y), due to the generality of the prohibition hadiths. The third is that the Imam's prayer is not invalidated, because the Prophet (peace be upon him) was an Imam, he spoke, and he built upon his prayer; however, the prayer of the followers (ma'mumun) who spoke is invalidated. Their following of Abu Bakr and Umar (may Allah be pleased with them) is not valid, for they spoke in response to the Prophet (peace be upon him), and answering him was obligatory upon them; nor is the following of Dhu al-Yadayn valid, because he spoke as one asking about a deficiency in the prayer at a time when such was possible, which is not present in our time. This narration is the choice of al-Khiraqi. This is restricted to speech concerning the state of the prayer, because the Prophet (peace be upon him) and his companions only spoke regarding its state; thus, the permissibility of speech is restricted by the arrival of the text (nass), as the need calls for that and not for other things, so drawing an analogy of other things to it is prohibited. As for one who speaks in the midst of the prayer without a salutation or the assumption of completion, his prayer is invalidated, whether he is an Imam or other than him, for the benefit of the prayer or otherwise. The Qadi mentioned these three narrations regarding that, and the words of al-Khiraqi allow for it due to the generality of his wording, which is the school of al-Awza'i, as he said: If a man said to the Imam, while he was reciting aloud in the Asr prayer, "It is Asr," his prayer would not be invalidated. Furthermore, the Imam may encounter a situation where he needs to speak, such as if he forgets the recitation in a unit and remembers it in the second; a unit has become invalid for him, so he needs to replace it with a unit that is, in the estimation of the followers, a fifth one, and they have no right to follow him in it, nor is there a way to inform them without speech. He has also doubted in his prayer, so he needs to inquire, and therefore speech has been permitted for him. I do not know of any text from the Prophet (peace be upon him), his companions, or an Imam regarding speech in a situation other than the one where he saluted, believing the prayer to be complete, then spoke after the salutation, and an analogy of speech in the midst of the prayer, while being aware of it, to this situation is impossible, because this is a state of forgetfulness where it is impossible to guard against speech, and it is also a state where ignorance of the prohibition of speech therein may occur to its possessor, so it is not valid to draw an analogy of what differs from it in these two matters to it. Nor is there any text regarding it; when text, analogy, and consensus are absent, the establishment of the ruling is precluded, for establishing it would be the initiation of a ruling without evidence, and there is no way to do so.