Sunan Abi Dawud Book 2, Hadith 409
He would recite Fatihat al-kitab in the last two surahs. Hammam added: He would prolong the first rak’ah but would not prolong the second so much; and he did so similarly in the afternoon prayer, and so in the morning prayer.
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.
We thought that by this (prolonging the first rak’ah). He (the prophet) meant that the people might join the first rak’ah.