The Messenger of Allah ﷺ commanded me to announce that prayer is not valid but with the recitation of Fatihat al-kitab and something more. (Using translation from Abū Dāʾūd 820)
أَمَرَنِي رَسُولُ اللهِ ﷺ أَنْ أُنَادِيَ لَا صَلَاةَ إِلَّا بِقُرْآنٍ بِفَاتِحَةِ الْكِتَابِ فَمَا زَادَ