قال الشيخ رحمه الله والمفروض من الصلاة اداؤها في وقتها واستقبال القبلة لها وتكبيرة الافتتاح والقراءة والركوع والتسبيح في الركوع والسجود والتسبيح في السجود والتشهد والصلاة على محمد وآله عليهم السلام فمن ترك شيئا من هذه الخصال التي ذكرناها عمدا في صلاته فلا صلاة له وعليه الاعادة ومن تركها ناسيا فلها احكام
The Shaykh (Al-Mufid), may Allah (swt) support him, said: "And that which is obligatory in prayer is its performance within its time, facing the Qiblah for it, the opening Takbir, the recitation, the bowing, the glorification in the bowing, the prostration, the glorification in the prostration, the tashahhud, and the sending of blessings upon Muhammad (saws) and his family, peace be upon them. So whoever deliberately leaves out any of these qualities that we have mentioned in his prayer, his prayer is invalid and he must repeat it. And whoever leaves them out due to forgetfulness, there are rulings pertaining to that."