Verse 185 of Surah Ali 'Imran.
It reminds every person that death is certain, that full reward is given on the Day of Resurrection, and that the life of this world is a fleeting enjoyment. The verse is a sober, often quoted reminder of what lasts and what does not.
- 3:185
كُلُّ نَفْسٍۢ ذَآئِقَةُ ٱلْمَوْتِ ۗ وَإِنَّمَا تُوَفَّوْنَ أُجُورَكُمْ يَوْمَ ٱلْقِيَٰمَةِ ۖ فَمَن زُحْزِحَ عَنِ ٱلنَّارِ وَأُدْخِلَ ٱلْجَنَّةَ فَقَدْ فَازَ ۗ وَمَا ٱلْحَيَوٰةُ ٱلدُّنْيَآ إِلَّا مَتَٰعُ ٱلْغُرُورِ
Kulu nafsin zaaa'iqatul mawt; wa innamaa tuwaffawna ujoorakum Yawmal Qiyaamati faman zuhziha 'anin Naari waudkhilal Jannata faqad faaz; wa mal hayaatud dunyaaa illaa mataa'ul ghuroor
Every soul will taste death, and you will only be given your [full] compensation on the Day of Resurrection. So he who is drawn away from the Fire and admitted to Paradise has attained [his desire]. And what is the life of this world except the enjoyment of delusion.