عَنْ عُبَادَةَ بْنِ الصَّامِتِ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَا صَلَاةَ لمن لم يقْرَأ بِفَاتِحَة الْكتاب»
وَفِي رِوَايَةٍ لِمُسْلِمٍ: «لِمَنْ لَمْ يَقْرَأْ بِأُمِّ الْقُرْآن فَصَاعِدا»
‘Ubada b. as-Samit reported God’s Messenger as saying, “He who does not recite Fatihat al-Kitab* is not credited with having observed prayer.”
*The first sura.
(Bukhari and Muslim.) A version by Muslim has “He who does not recite Umm al-Qur’an (the first sura and something more.”