Musannaf Ibn Abi Shayba 22:360

Husayn ibn Ali narrated to us, from Za'idah, from 'Asim, from al-Musayyib, who said: Abdullah said: "The *Tiwal* (long surahs) are like the Torah, the *Mi'un* (surahs of about one hundred verses) are like the Gospel, and the *Mathani* (surahs often recited) are like the Psalms. And the rest of the Quran is an excellence."