فَكَيفَ تَتَّقونَ إِن كَفَرتُم يَومًا يَجعَلُ الوِلدانَ شيبًا

السَّماءُ مُنفَطِرٌ بِهِ ۚ كانَ وَعدُهُ مَفعولًا

So, if you disbelieve, how will you avoid the day which will make children white-headed,

and wherein the sky will be rent apart? His promise is bound to be fulfilled.

EXEGESIS

The word shīb in verse 17 is the plural of ashyab, and in meaning is the opposite of youthfulness.^{‎[1]Mizan, 20/69.}

EXPOSITION

Verse 17 wishes to say: why do you, O Meccans, disbelieve and oppose the message of God, when you are weaker, less affluent, and fewer in numbers than the Pharaoh and his hosts? And how are you deceived and beguiled by your little wealth and fewer numbers?!

Ṭūsī writes that this verse is in the form of an example of the horrendous effects of that day^{‎[2]Tibyan, 10/167.} which will make children white headed, this being an indication of the intensity of the distress of that day and not its length.^{‎[3]Mizan, 20/69.} Imam Ali (a) is reported to have said: ‘Beware of the day when deeds will be scrutinised and investigated, the day on which the shaking and quaking will intensify, and when little children will turn hoary.’^{‎[4]Daqaiq, 14/505.}

Verses 17 and 18 express the intensity of punishment on the Day of Judgement. The sky will be rent apart or sundered due to it.^{‎[5]Amthal, 19/142.} Refer to verse 11 of Sūrat al-Takwīr where the phenomenon of the renting apart of the sky has been dealt with in some detail.

This verse, although describing a future event and translated into English as such, is actually in the past tense according to the Arabic. Ṭūsī writes that what God promises necessarily occurs, therefore even though the Day of Judgement, which this verse describes, is to take place in the future, the verse is in the past tense because what God promises is to occur and so it is as if it has already occurred.^{‎[6]Tibyan, 10/168.}

[1] Mizan, 20/69.
[2] Tibyan, 10/167.
[3] Mizan, 20/69.
[4] Daqaiq, 14/505.
[5] Amthal, 19/142.
[6] Tibyan, 10/168.