Аль-Кахф 18:21

And so, just as We aroused them, it was that We disclosed them, [to] their people and the believers, that they, that is, their people, might know that God’s promise, of resurrection, is true: by virtue of the fact that One Who has the power to make them sleep for [such] a long period of time, or sustain them in that state without nourishment, also has the power to resurrect the dead; and that, as for the Hour, there is no doubt, no uncertainty, concerning it. Behold (idh adverbially qualifies a‘tharnā, ‘We disclosed’) they were disputing, that is, the believers and the disbelievers, among themselves their affair, the affair of the youths, with regard to building something around them [as a monument]; so they, the disbelievers, said, ‘Build over them, that is, around them, a building, to cover them up; their Lord knows them best.’ Those who prevailed regarding their affair, the affair of the youths, namely, the believers, ‘We will verily set up over them, around them, a place of worship’, for prayers to be performed therein. And this indeed took place at the entrance of the cave.