It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "My Lord gave me the Seven Long (Surahs, al-Sab' al-Tiwal) in place of the Torah, and the Mi'in (the surahs of about a hundred verses) in place of the Injil, and He favoured me with the Mufassal surahs."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7972