Sunan Abi Dawud Book 2, Hadith 407
In every prayer there is a recitation. We make you listen what the Messenger of Allah(ﷺ) made us listen, and we keep hidden from you what he kept hidden from us.
I heard the apostle of Allah (ﷺ) say: A man returns after saying his prayer while a tenth part of his prayer, or a ninth part, or an eight part, or a seventh part, or a sixth part, or a fifth part, or a third part, or half of it, is recorded for him.
The apostle of Allah (ﷺ) used to lead us in prayer and recite in the first two rak’ahs of the noon prayers Fatihat al-kitab and two surahs, and he would sometimes recite loud enough for us to hear the verse. He would prolong the first rak’ah of the noon prayer and shorten the second; and he did so in the morning prayer.
Abu Dawud said: Musaddad did not mention the words fatihat al-kitab and surah.