Ibn Mas'ud reported God's messenger 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.
Narrated ‘Amr b. Shu'aib quoted the authority of his father from his grandfather who said that the Prophet heard some people disagreeing about
the Qur’an and said, “It was just on this account that your predecessors
perished:
they set parts of God’s Book against others, whereas God's
Book was sent down only to be consistent; so do not use parts to falsify
others. Speak about as much of it as you know, but where you are ignorant entrust it to him who knows.” Ahmad and Ibn Majah transmitted it.