Abd al-Rahman bin Nafi' bin Jubayr narrates from his father, from his grandfather, who said: the Prophet (peace and blessings be upon him) used to say in his bowing (ruku') "Subhana Rabbiyal-Azim" and in his prostration "Subhana Rabbiyal-A'la".
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1559