Sunan Abi Dawud Book 2, Hadith 422

Zaid b. Thabit asked me: Why do you recite short surahs in the sunset prayer? I saw the Messenger of Allah (May peace be upon him) reciting two long surahs at the sunset prayers. I asked him: which are those two long surahs? He replied: Al-A’raf(surah vii) and al-an’am(surah vi). I ( the narrator Ibn Juraij) asked Ibn Mulaikah (about these surahs): He said on his own accord: Al-ma’idah (surah v.) and al-A’raf(furah vii.)