You are the Most Glorious, the Most Holy, and the Lord of the angels and of the Spirit

‘Ā’ishah (may Allah be pleased with her) reported that the Messenger of Allah (may Allah’s peace and blessings be upon him) used to recite in his bowing and prostration: "You are the Most Glorious, the Most Holy, and the lord of the angels and of the Spirit."
"You are the Most Glorious, the Most Holy" is a superior form of glorification. "Lord of the angels" refers to the angels who are the soldiers of Allah; a world which we do not see. "the Spirit" is Jibrīl, who is the best of the angels. One should repeat this remembrance during the bowing and prostration.
"the Most Holy" is one of Allah noble names. It is to deem Allah far removed from any imperfection along with glorifying and exalting Him. "The Most Glorious" is another of Allah's noble names.