On the authority of Abu Hurayrah (may Allah be pleased with him), who said that the Messenger of Allah (PBUH) said: Allah said:

I have prepared for My righteous servants what no eye has seen and no ear has heard, not has it occurred to human heart. Thus recite if you wish (1): And no soul knows what joy for them (the inhabitants of Paradise) has been kept hidden (Quran Chapter 32 Verse 17).

(1) The words "Thus recite if you wish" are those of Abu Harayrah.

It was related by al-Bukhari, Muslim, at-Tirmidhi and Ibn Majah.