Is the phrase, "In Paradise there is what no eye has seen, nor ear has heard, nor has it ever occurred to the mind of a human," a Hadith or a Qur'anic verse, and how can it be reconciled with the fact that Adam (peace be upon him) saw Paradise and heard what was in it before his descent to Earth?

This hadith was narrated by Imam Ahmad from Abu Hurayrah from the Prophet, may Allah bless him and grant him peace. Similar narrations are found in Al-Bukhari and Muslim. Its purport is that the inhabitants of Paradise will enjoy bliss, their clothes will not wear out, and their youth will not fade. Allah has prepared for them therein what no eye has seen, no ear has heard, and no human heart has conceived, in accordance with the Almighty’s saying: "No soul knows what has been hidden for them of comfort for eyes, as reward for what they used to do." The presence of Adam, peace be upon him, in Paradise does not contradict this hadith, as he was not informed of all its delights.