The Quranic Text & Ali’s Version:
وَيَسْتَعْجِلُونَكَ
بِالْعَذَابِ...
29:53. They ask thee to hasten on the Punishment (for them):
The rejecters of Faith throw out a challenge out of bravado: "Let us see if you can hasten the punishment on us!"
This is a vain taunt. Allah's Plan will take its course, and can neither be delayed nor hastened. It is out of His Mercy that He gives respite to sinners, in order that they may have a chance of repentance. If they do not repent, the Punishment must certainly come to them -and on a sudden, before they perceive that it is coming! And then it will be too late for repentance.
...وَلَوْلَا أَجَلٌ مُّسَمًّى لَجَاءهُمُ الْعَذَابُ...
had it not been for a term (of respite) appointed, the Punishment would certainly have come to them:
...وَلَيَأْتِيَنَّهُم بَغْتَةً وَهُمْ لَا يَشْعُرُونَ ﴿٥٣﴾
and it will certainly reach them, -- of a sudden, while they perceive not!
Asad’s Version:
(29:53)
Now they challenge thee to hasten the coming upon them of [God's] chastisement: 51 and indeed, had not a term been set [for it by God], that suffering would already have come upon them! But indeed, it will most certainly come upon them of a sudden, and they will be taken unawares.
[[ Asad’s note - 51 See note 32 on 18:32. ]]