The Quran

وَإِذ صَرَفنا إِلَيكَ نَفَرًا مِنَ الجِنِّ يَستَمِعونَ القُرآنَ فَلَمّا حَضَروهُ قالوا أَنصِتوا ۖ فَلَمّا قُضِيَ وَلَّوا إِلىٰ قَومِهِم مُنذِرينَ

Muhammad Asad

AND LO!¹ We caused a group of unseen beings to incline towards thee, [O Muhammad,]² so that they might give ear to the Qur'an; and so, as soon as they became aware of it,³ they said [unto one another], "Listen in silence!" And when [the recitation] was ended, they returned to their people as warners.⁴

See surah 2, note 21 The connection between this passage and the preceding one apparently lies in the fact that whereas "those who are lost in sin" (of whom the tribe of 'Ad is given as an example) refuse to heed God's messages, the "unseen beings" spoken of in the sequence immediately perceived their truth and accepted them.
The term nafar signifies a group of more than three and up to ten persons. The occurrence mentioned in this passage - said to have taken place in the small oasis of Nakhlah, on the way leading from Mecca to Ta'if (Tabari) - is evidently identical with that described in 72:1-i 5; for a tentative explanation, see note I on 72:1.
Lit., "as soon as they attended to it", i.e., to its recitation by the Prophet.
I.e., as preachers of the Qur'anic creed. The expression "as warners" connects with the preceding references to "warning messages".