Translation:

15. Like those who lately preceded them they have tasted the evil result of their conduct and (in the Hereafter there is) for them a grievous Penalty

Notes (Tafseer)

5392. The immediate reference was probably to the Jewish goldsmith tribe of the Qainuqa, who were also settled in a fortified township near Madinah. They were also punished and banished for their treachery, about a month after the battle of Badr, in which the Makkan Pagans had suffered a signal defeat, in Shawwal, A.H. 2. The Nadhir evidently did not take that lesson to heart. The general meaning is that we must learn to be on our guard against the consequences of treachery and sin. No fortuitous alliances with other men of iniquity will save us.