And when it was said, 'Indeed, the promise of Allāh is truth and the Hour [is coming] - no doubt about it,' you said, 'We know not what is the Hour. We assume only assumption, and we are not convinced.'"
When it is said to you: “Allah’s promise, in which He has promised His servants He will resurrect them and reward them, is true without doubt, and the Hour is true without doubt, so work for it”, you say: “We do not know what this Hour is. We only assume doubtfully that it is coming and we are not convinced it will come”.