Musnad Ahmad 1153:2052

Rawh narrated to us, he said: Shu'bah narrated to us, he said: I heard Qatadah, he said: I heard Mutarrif ibn 'Abdullah, from 'Aishah, she said: The Messenger of Allah, peace and blessings of Allah be upon him, used to say in his bowing (ruku') and his prostration (sujud): "Most Glorified, Most Holy, Lord of the angels and the Spirit."