Ibn Mas’ud (may Allah be pleased with him) reported Allah’s Messenger (peace be upon him) as saying, “The Qur’an was sent down in seven modes. Every verse in it has an external and an internal meaning, and every interdiction has a source of reference.” Baghawi transmitted it in Sharh as-sunna.
Mishkat al-Masabih 238, Book 2, Hadith 35
