102:5
كَلَّا لَوْ تَعْلَمُونَ عِلْمَ ٱلْيَقِينِ
kallā law taʿlamūna ʿil'ma l-yaqīni
No indeed! If only you knew for certain.
Nay! If you knew with a sure knowledge (the end result of piling up, you would not have been occupied yourselves in worldly things).