Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.137.

It is sunnah for the person to recite a section of the Qur’an after al-Fatihah during the two rak’ah of the morning prayer and the Friday prayer, and the first two rak’ah of the noon, afternoon, sunset and night prayers, and in all of the rak’ah of the superogatory prayers. Abu Qatadah reported that the Prophet, upon whom be peace, would recite al-Fatihah and some surah in the first two rak’ah of the noon prayer, and only al-Fatihah in the last two rak’ah. Sometimes he would recite some verses. The first rak’ah’s recital would be longer than the second. That was how it was done in the afternoon and morning prayers. This is related by al-Bukhari, Muslim and by Abu Dawud, who adds, “We think he did that in order to allow people to catch the first rak’ah.”

Jabir ibn Sumrah reported that the people of Kufah complained about Sa’d to ‘Umar, causing ‘Umar to dismiss him and replace him with ‘Ammar. They had many complaints about Sa’d, even claiming that he did not pray properly. ‘Umar sent for him and said, “O Abu Ishaq (Sa’d), these people claim that you do not pray properly.” Sa’d replied, “By Allah, I prayed with them in the same manner that the Messenger of Allah, upon whom be peace, prayed with us, and I never shortened it in any way. I would lengthen the first two rak’ah of the night prayer and shorten the last two.” Said ‘Umar, “This is what I expected of you.” He sent him back to Kufah with one or two people to ask the people of Kufah about him. All of the people praised him until they went to the mosque of the tribe of ‘Abs. A man named Usamah ibn Qatadah, also known as Abu Sa’da, stood and said, “Since I am under oath I must inform you that Sa’d never accompanied the army, did not distribute the booty justly, and was not just in his legal verdicts. Sa’d then said, “I pray to Allah for three things: O Allah, if this slave of Yours is lying and stood only for show, then give him a long life, increase his poverty and put him to trials.” Years later, when Usamah was asked how he was doing, he would answer that he was an old man in trial due to Sa’d’s supplication. ‘Abdul-Malik (one of the narrators) said that he had seen the man afterwards with his eyebrows overhanging his eyes due to old age, and he would tease and assault the young girls along the paths. (Related by al-Bukhari.)

Said Abu Hurairah, “A recitation should be done in every prayer. What we heard from the Prophet, upon whom be peace, we let you hear. What he was silent about, we are silent about with you. If one does not add anything to al-Fatihah, it is sufficient. If one does add something, it is good.” (Related by al-Bukhari.)