"It is He Who has sent down to you (Muhammad SAW) the Book (this Quran). In it are Verses that are entirely clear, they are the foundations of the Book [and those are the Verses of Al-Ahkam (commandments, etc.), Al-Fara'id (obligatory duties) and Al-Hudud (legal laws for the punishment of thieves, adulterers, etc.)]; and others not entirely clear. So as for those in whose hearts there is a deviation (from the truth) they follow that which is not entirely clear thereof, seeking Al-Fitnah (polytheism and trials, etc.), and seeking for its hidden meanings, but none knows its hidden meanings save Allah. And those who are firmly grounded in knowledge say: "We believe in it; the whole of it (clear and unclear Verses) are from our Lord." And none receive admonition except men of understanding. (Tafsir At-Tabari)."
(Surah 3: Al-'Imran (The Family Of Imran); verse 7)