Muwaththa' Malik · #186
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 .
English
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