Prayer (Kitab Al-Salat): Detailed Injunctions about Ramadan
Dawud :: Book 6 : Hadith 1391
Narrated Ibn Mas'ud:
Alqamah and al-Aswad said: A man came to Ibn Mas'ud. He said: I recite the mufassal surahs in one rak'ah. You might recite it quickly as one recites verse (poetry) quickly, or as the dried dates fall down (from the tree).
But the Prophet (peace_be_upon_him) used to recite two equal surahs in one rak'ah; he would recite (for instance) surahs an-Najm (53) and ar-Rahman (55) in one rak'ah, surahs Iqtarabat (54) and al-Haqqah (69) in one rak'ah, surahs at-Tur (52) and adh-Dhariyat (51) in one rak'ah, surahs al-Waqi'ah (56) and Nun (68) in one rak'ah, surahs al-Ma'arij (70) and an-Nazi'at (79) in one rak'ah, surahs al-Mutaffifin (83) and Abasa (80) in one rak'ah, surahs al-Muddaththir (74) and al-Muzzammil (73) in one rak'ah, surahs al-Insan (76) and al-Qiyamah (75) in one rak'ah, surahs an-Naba' (78) and al-Mursalat (77) in one rak'ah, and surahs ad-Dukhan (44) and at-Takwir (81) in one rak'ah.