Volume 1 · Book 12 · Hadith 731
Narrated Marwan bin Al-Hakam: Zaid bin Thabit said to me, "Why do you recite very short S&ras in the Maghrib prayer while I heard the Prophet reciting the longer of the two long Suras?"
— Sahih Bukhari, Volume 1, Book 12: Characteristics of Prayer, Hadith #731