Authentic Supplication Number 8.
The Messenger of Allah said: “There are two phrases which are light on the tongue, heavy in the balance, and beloved to the All Merciful; Subhana ‘allahi wa bihamdihi, Subhana ‘allahil-`atheemi (9).”
(9) Glorified is Allah, and [I am] in His praise; Glorified is Allah The Magnificent.
Reported in Saheeh ‘Al-Bukhari and Saheeh Muslim. ‘Al-Albani included this hadeeth in The Authentic of Good Sayings as #8.