Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 70
Narrated 'Aisha:
Allah's Apostle recited the Verse:--
"It is He who has sent down to you the Book. In it are Verses that are entirely clear, they are the foundation of the Book, others not entirely clear. So as for those in whose hearts there is a deviation (from the Truth ). follow thereof that is not entirely clear seeking affliction and searching for its hidden meanings; but no one knows its hidden meanings but Allah. And those who are firmly grounded in knowledge say: "We believe in it (i.e. in the Qur'an) the whole of it (i.e. its clear and unclear Verses) are from our Lord. And none receive admonition except men of understanding." (3.7)
Then Allah's Apostle said, "If you see those who follow thereof that is not entirely clear, then they are those whom Allah has named [as having deviation (from the Truth)] 'So beware of them."