Surah 23. Al-Muminun, Ayah 100

Lit., "in respect of that which (fi-ma) I have left", comprising both the omission of good and the commission of bad deeds.

 Meaning, once they are dead, they will never return to the world.

The unrighteous will ask for another chance. But it will be too late then. The time for repentance will then have passed.

Their request will mean nothing. It will be treated merely as an empty word of excuse. They had plenty of chances in this life. Not only did they reject them, but they did not even believe in Allah or ask for His assistance.

Barzakh: a partition, a bar or barrier; the place or state in which people will be after death and before Judgment. Cf. xxv. 53 and Iv. 20. Behind them is the barrier of death, and in front of them is the Barzakh, partition, a quiescent state until the judgment comes.