What is the difference between saying: "May Allah hear, and to Him be all praise," and saying: "May Allah hear him who praises Him"? What is the legal ruling of the first phrase in Sharia, and what is its linguistic meaning?

The prescribed "Tasmee'" (utterance when rising from Ruku') is "Sami' Allahu liman hamidah" (Allah hears those who praise Him), without the addition of the letter waw (و). Its meaning is that Allah has answered the supplication of those who praised Him. This is based on the Hadith: "The Imam is appointed to be followed. So when he says: 'Sami' Allahu liman hamidah,' then say: 'Rabbana wa laka al-hamd' (Our Lord, and to You be all praise)." As for adding the waw, it is not legislated because it has not been reported and because the meaning is complete without it.