وَإِذَا قِيلَ إِنَّ وَعْدَ ٱللَّهِ حَقٌّ وَٱلسَّاعَةُ لَا رَيْبَ فِيهَا قُلْتُم مَّا نَدْرِى مَا ٱلسَّاعَةُ إِن نَّظُنُّ إِلَّا ظَنًّا وَمَا نَحْنُ بِمُسْتَيْقِنِينَ
Wai tha qeela inna waAAda All a hi h aqqun wa al ss a AAatu l a rayba feeh a qultum m a nadree m a a l ss a AAatu in na th unnu ill a th annan wam a na h nu bimustayqineen a for when it was said, 'Behold, God's promise always comes true, and there can be no doubt about [the coming of] the Last Hour' - you would answer, 'We do not know what that Last Hour may be: we think it is no more than an empty guess, and [so] we are by no means convinced!'"
 - Mohammad Asad
When it was said, "the promise of Allah is true and the Hour of Judgement is sure to come. You used to say, `We don't know what the Hour of Judgement is: we think it is just a conjecture, we are not convinced.'"
 - Muhammad Farooq-i-Azam Malik
And whenever it was said 'to you', 'Surely Allah's promise 'of judgment' is true and there is no doubt about the Hour,' you said 'mockingly', 'We do not know what the Hour is! We think it is no more than speculation, and we are not convinced 'that it will ever come'.''
 - Mustafa Khattab
And when it was said: Lo! Allah's promise is the truth, and there is no doubt of the Hour's coming, ye said: We know not what the Hour is. We deem it naught but a conjecture, and we are by no means convinced.
 - Marmaduke Pickthall
"And when it was said that the promise of Allah was true and that the Hour there was no doubt about its (coming) ye used to say `We know not what is the Hour: we only think it is an idea and we have no firm assurance.'" 4769
 - Abdullah Yusuf Ali