Chapter on the Manner of Prayer, Explanation of the Fifty-One Rak‘ahs; The Order, Recitation, Tasbih in Bowing and Prostration, Qunut, and What is Obligatory and Recommended Therein

And from him, from Ahmad ibn Muhammad ibn Abi Nasr, who said: I said to Abu al-Hasan عليه السلام, peace be upon him: “May I be your ransom, the ‘tashahhud’ which is said in the second rak‘ah, is it sufficient if I say it in the fourth [rak‘ah] as well?” Imam عليه السلام said: “Yes.”