Hadith: Allah, the Almighty, said: "I have prepared for My righteous slaves what no eye has ever seen, no ear has ever heard, and no human heart has ever conceived," and recite if you wish: {And no soul knows what delight awaits them as the reward for their deeds}

عن أبي هريرة رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «قال الله تعالى : أَعْدَدْتُ لعِبَادي الصَّالحين ما لا عَيْنٌ رأَت، ولا أُذُنٌ سَمِعَت، ولا خَطَر على قَلب بَشَر، واقْرَؤُوا إن شِئْتُمْ: (فلا تَعلم نفس ما أُخْفِي لهم من قُرَّة أَعْيُنِ جَزَاء بما كانوا يعملون). عن سهل بن سعد رضي الله عنه قال: شَهدت من النبي صلى الله عليه وسلم مَجْلِسَا وَصَفَ فيه الجَنَّة حتى انتهى، ثم قال في آخر حديثه: «فيها ما لا عَيْنٌ رأَت، ولا أُذُنٌ سَمِعَت، ولا خَطَر على قَلب بَشَر» ثم قرأ:(تتجافى جُنُوبهم عن المَضَاجِع) إلى قوله تعالى :(فلا تعلم نفس ما أُخْفِي لهم من قُرَّة أَعْيُنِ).
[صحيح] - [حديث أبي هريرة متفق عليه. حديث سهل بن سعد رواه مسلم]

Abu Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Allah, the Almighty, said: 'I have prepared for My righteous slaves what no eye has ever seen, no ear has ever heard, and no human heart has ever conceived,' and recite if you wish: {And no soul knows what delight awaits them as the reward for their deeds.} [Sūrat As-Sajdah: 17]" Sahl ibn Sa‘d (may Allah be pleased with him) reported: I witnessed a gathering wherein the Prophet (may Allah's peace and blessings be upon him) described Paradise until the end, then he said at the end of his speech: "Therein is what no eye has ever seen, no ear has ever heard, and no human heart has ever conceived." Then he recited: {They arise from [their] beds ... no soul knows what delight awaits them.} [Sūrat As-Sajdah: 16-17]"
Authentic hadith - Narrated by Muslim

Explanation

Meaning of the Hadīth: Allah, the Exalted, has prepared for His righteous slaves – those who fulfilled His commands and avoided His prohibitions – "What no eye has ever seen" of astonishing beauty and attractions and "no ear has ever heard" of delightful sounds and amazing descriptions. The sight and hearing were specifically mentioned because they are the means to realizing most of what is perceptible, followed by taste and smell, whereas touching comes at the end. "And no human heart has ever conceived;" meaning: of the everlasting delight that has been prepared for them in Paradise. Paradise is better than anything that they can imagine or dream of, because humans can only imagine what they know and is close to their imagination. The bliss of Paradise is far above that, and this is one of the ways in which Allah honors them for fulfilling His commands and avoiding His prohibitions, as well as for suffering in the cause of Allah. Indeed the reward is from the same type of the deed. "Recite if you wish," and in another narration: "Then he recited this verse: {And no soul knows what delight awaits them as the reward for their deeds.} [Sūrat As-Sajdah: 17]" The meaning of "No soul knows" includes all the souls of all creatures, since it is an unspecified negation. That is to say: no one knows {what delight awaits them} from abundant good, delight, happiness, and joy. For just as they used to pray at night, supplicate, and hide their good deeds, He will reward them with the same type of deed by hiding their reward, and that is why He said: {as the reward for their deeds.}