It is narrated from Hazrat Abu Umamah (may Allah be pleased with him) that when the Noble Prophet (peace and blessings be upon him) would begin the prayer, he would say "Allahu Akbar" three times, "Subhan Allah" three times, and "La ilaha illallah" three times, then he would recite this supplication: "O Allah, I seek refuge in You from the prodding of Satan, his blowing, and his shirk."