It is narrated from Sayyiduna Abdullah (may Allah be pleased with him) that he said: "Give every surah its due in bowing and prostration, for the Messenger of Allah (peace and blessings be upon him) would recite only twenty surahs in ten rak'ahs."
Hadith Referenceالمعجم الأوسط / باب العين / 4573
Hadith Takhrij«أخرجه البزار فى «مسنده» برقم: 1572، والطبراني فى «الكبير» برقم: 9856»