Sahih Al Bukhari – Book of Prophetic Commentary On The Qur'an (Tafseer Of The Prophet (pbuh))
Volumn 006, Book 060, Hadith Number 302.
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Narated By Abu Huraira : Allah's Apostle said, "Allah said, 'I have prepared for my pious worshipers such things as no eye has ever seen, no ear has ever heard of, and nobody has ever thought of.' " Abu Huraira added: If you wish you can read: 'No soul knows what is kept hidden (in reserve) for them of joy as reward for what they used to do.' "32.17.