A. Yusuf Ali:Translation:
Of no effect is the repentance of those who
continue 526 to do evil, until death faces one of
them, and he says, "Now have I repented indeed;" nor
of those who die rejecting Faith: for them have We
prepared a punishment most grievous.

Muhammad Asad:Translation:
whereas repentance shall not be accepted from those who do evil deeds until their dying hour and then say, 16 "Behold, I now repent"; nor from those who die as deniers of the truth: it is these for whom We have readied grievous suffering.
526 Note the fine touch. A sin may be fashionable, and people may sin together without compunction. When one of them is faced with Death, he repents, but that sort of repentance is no good. For more detailed discussion, (Cf. notes to 24:2-6 and 4:15 .) (Eds.)