Hadith 145

Bulugh al-Maram

Book 2: The Book of Prayer
وَلِأَبِي دَاوُدَ : { ثُمَّ اِقْرَأْ بِأُمِّ اَلْقُرْآنِ وَبِمَا شَاءَ اَللَّهُ } 1‏
And Abu Dawud has "Then read the Ummul-Qur'an (i.e. Surah al-Fatiha) and what ever Allah wishes".