It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that when the Messenger of Allah (peace and blessings be upon him) raised his head from bowing, he would say 'Sami'allahu liman hamidah' (Allah has heard the one who praised Him), then he said: 'Rabbana lakal-hamd mil'as-samawati wa mil'al-ardi wa mil'a ma shi'ta min shay'in ba'd' (Our Lord, to You belongs all praise, filling the heavens and filling the earth, and filling whatever else You will thereafter).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2607