—the very threshold of the doorway.

What is meant is that their dog, which accompanied them when they separated from their people, stayed loyally with them yet did not enter the cave itself; rather, it lay at the entrance with its fore-legs stretched out on the threshold. This comportment was both a sign of the dog’s good manners and part of the honour shown to the youths, for the angels do not enter a house in which there is a dog. Such is the power of attachment: even their dog was preserved because it kept their company—‘whoever loves a people shares in their happiness.’ If this is true of a mere dog, what then of a person who follows the righteous and himself deserves honour?

Many storytellers and Qur’anic commentators have woven long accounts about this dog, most of them taken from Israelite reports; much of that material is baseless and devoid of benefit—such as their disputes over its name and colour.

As for the scholars’ disagreement over where the cave was located, many say it lay in the land of Aylah; others, in Nineveh; others, in the Balqāʾ; still others, ‘in the territories of Byzantium,’ and this last view seems more plausible—Allah knows best.

After the Almighty had set forth the most useful part of their story—describing their state so vividly that the listener almost sees them in the cave, how they were turned from side to side, and how their dog stretched out its paws at the threshold—He said:
‘Had you looked upon them, you would surely have turned away in flight and been filled with dread of them.’
That is, because of the awe and majesty that surrounded them in their extraordinary condition. The address here is most likely to humankind in general, not exclusively to the Messenger ﷺ, just as in His words, ‘So what yet makes you, O man, deny the Judgment?’ (al-Tīn 7). Human nature ordinarily recoils from sights that inspire awe, which is why He said, ‘Had you looked upon them, you would surely have turned away in flight and been filled with dread.’ The verse also shows that hearing a report is not the same as direct witnessing, as the Prophetic hadith states; for the report has reached us, yet we have neither fled nor felt terror.

The Most High then related that He roused them from their sleep after three hundred and nine years. When they awoke, they said to one another: ‘How long have we stayed?’ They answered, ‘We have remained a day, or part of a day.’ They then said, ‘Your Lord knows best how long you have stayed; so send one of you with this silver of yours to the city…’—meaning, with these coins they had with them—to the city, which, it is said, was called Difsūs. ‘Let him see which food is purest’—that is, most lawful and wholesome—‘and bring you provision from it.’ This displays their asceticism and pious caution. ‘And let him be courteous’—in the way he enters the city—‘and let him not make anyone aware of you. For if they gain the upper hand over you, they will stone you or force you back into their religion, and then you will never prosper.’ That is, if you were to return to their creed after Allah has delivered you from it. All of this was because they assumed they had slept only a day, or part of a day, or perhaps a little more; they never imagined that their slumber had exceeded three hundred years.