In another narration, there is this addition: When the Imam says "Sami' Allahu liman hamidah," the person behind should recite: "Sami' Allahu liman hamidah, Allahumma Rabbana lakal hamd." Allah has heard the praise of the one who praised Him, "O Allah! O our Lord! All praise is exclusively for You."
Hadith Referenceسنن الدارقطني / كتاب الصلاة / 1306
Hadith Takhrij«أخرجه البيهقي فى((سننه الكبير)) برقم: 2659، والدارقطني فى ((سننه)) برقم: 1306، وابن أبى شيبة فى ((مصنفه)) برقم: 2615»