Ibn Qutaybah

We're taking it away from that literal meaning to understand it, to refer to an intense moment on the day of resurrection.

Ibn al-Qutayba said, The root of this expression is that when a person is faced with a serious matter requiring full effort, it is said he has rolled up his sack he's rolled up his shin like one might do with their pant legs they roll up their pant legs meaning they're about to get busy Thus uncovering the shin, this becomes a metaphor for hardship.

That's what he says, Ibn Qutayba.

Hence the interpretation of the verse is, on the day of the affair, it becomes intense.