مُوَطَّأُ مَالِكٍ
Muwatta Malik 187
Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ أَبِي نُعَيْمٍ، وَهْبِ بْنِ كَيْسَانَ أَنَّهُ سَمِعَ جَابِرَ بْنَ عَبْدِ اللَّهِ، يَقُولُ مَنْ صَلَّى رَكْعَةً لَمْ يَقْرَأْ فِيهَا بِأُمِّ الْقُرْآنِ فَلَمْ يُصَلِّ إِلاَّ وَرَاءَ الإِمَامِ .
Yahya related to me from Malik from Abu Nuaym Wahb ibn Kaysan that he heard Jabir ibn Abdullah say, "Someone who prays a raka without reciting the umm al-Qur'an in it has not done the prayer except behind an imam."
Arabic/English book reference: Book 3, Hadith 40