Amr bin 'Asim al-Kalabi عمرو بن عاصم الكلابي · Chapters on Supplication

when the Messenger of Allah would stand for the obligatory prayer, he would raise his hands to the level of his shoulder, and he would do this lā manjā minka wa lā malja’a illā ilaik, astaghfiruka wa atūbu ilaik).” Then he would recite, then when he would bow, his speech in his Ruku`, would be to say: “O Allah, to You have I bowed, and in You have I believed, and to You have I submitted (in Islam), and You…

“The Prophet (ﷺ) heard a man supplicating in his Salat but he did not send Salat upon the Prophet (ﷺ), so the Prophet (ﷺ) said: ‘This one has rushed.’ Then he called him and said to him, or to someone other than him: ‘When one of you performs Salat, then let him begin by expressing gratitude to Allah and praising Him. Then, let him send Salat upon the Prophet (ﷺ), then let him supplicate after that, whatever he wishes.’”