Translation:

29. Behold We turned towards thee a company of Jinns (quietly) listening to the Qur'an: when they stood in the presence thereof they said "Listen in silence!" When the (reading) was finished they returned to their people to warn (them of their sins).

Notes (Tafseer)

4809. A company of Jinns. Nafar (company) may mean a group of from three to ten persons. For Jinns, see n. 929 to vi. 100. They listened to the reading of the Qur-an with great respect. The next verse shows that they had heard of the Jewish religion, but they were impressed with the Message of Islam, and they seem to have gone back to their people to share the Good News with them.