فَلَا تَعۡلَمُ نَفۡسٞ مَّآ أُخۡفِيَ لَهُم مِّن قُرَّةِ أَعۡيُنٖ جَزَآءَۢ بِمَا كَانُواْ يَعۡمَلُونَ ١٧
And no soul knows what has been hidden for them of comfort for eyes [i.e., satisfaction] as reward for what they used to do.
Translation: Saheeh International (English)
Each word's meaning and sound
So no one knows what things Allah has prepared for it in terms of bringing coolness and joy to the eyes, as a reward for the good deeds it would do in the world. It is a reward that no one except Allah can comprehend, due to its greatness.
Al-Mukhtasar in interpreting the Noble Quran