Is the response to Salam permissible if delivered in reverse order, such as saying 'Alaykum As-Salam'?
Chapter on the Description of Prayer
Al-Mughni
Book of Prayer
Primary text
Responding to the greeting of Salam with the reversed phrase, 'Alaykum As-Salam,' is not sufficient (i.e., does not fulfill the obligation). The Prophet, peace be upon him, established the order of the greeting and its response, commanding it to be delivered in the proper sequence. Evidence supporting this prohibition is the hadith where the Prophet told Abu Tamimah, 'Do not say 'Alayka As-Salam,' for 'Alayka As-Salam' is the greeting of the dead.' This hadith is narrated by Ahmad in the Musnad. Furthermore, since the greeting is an utterance used at the beginning or end of prayer, it is not permissible to deliver it in a reversed manner, similar to the Takbir.
Supporting text
There is another viewpoint, which is the opinion of Al-Shafi'i, asserting that the reversed response is sufficient because the intended meaning is conveyed, and the greeting is not considered Quranic recitation where strict adherence to the prescribed order (*nadhz*) is required.