When the Prophet ﷺ opened the prayer, he would say, "Glory be to You, Allah, and praise be to You. Blessed is Your name, exalted is Your majesty, and there is no god but You."
أخبرنا عبيد الله بن فضالة بن إبراهيم قال أنبأنا عبد الرزاق قال أنبأنا جعفر بن سليمان عن علي بن علي عن أبي المتوكل
أن النبي ﷺ كان إذا افتتح الصلاة قال سبحانك اللهم وبحمدك تبارك اسمك وتعالى جدك ولا إله غيرك
[Its chain is hasan]. Reported by Abu Dawud in the Book of Prayer, chapter on those who held that one should open with "Glory be to You, O Allah, and praise be to You," hadith 775, and Tirmidhi, hadith 242, and Ibn Majah, hadith 804, from the hadith of Jafar, by this chain. He is hasan al-hadith, as I established in Nail al-Maqsud. The hadith is also in al-Kubra, hadith 972, and Ibn Khuzayma graded it sahih, hadith 467.