It is narrated from Hazrat Uqbah bin Aamir (may Allah be pleased with him) that when this blessed verse "Fasabbih bismi rabbikal azeem" was revealed, the Prophet (peace and blessings be upon him) said: "Include it in your bowing (ruku')" (that is why 'Subhana Rabbiyal Azeem' is said in ruku'). And when "Sabbih isma rabbikal a'la" was revealed, he said: "Include it in your prostration (sajdah)" (that is why 'Subhana Rabbiyal A'la' is said in sajdah).