﴿ كَلَّا لَوْ تَعْلَمُونَ عِلْمَ ٱلْيَقِينِ ﴾

“Nay, if you could but understand [it] with an understanding [born] of certainty,”

But no. Did you but know with the knowledge of certainty. If you had the knowledge of certainty and the eye of certainty that you must pass over the steep road of death and you must prepare what you need for the journey of the resurrection, then surely your boasting and vying for increase in property and provisions would be less and your eagerness for obedience and worship would be more.