From Ibn Kathir’s The Signs before the Day of Judgment.
Answer:
Ayat and Ahadith about the Hour
Allah (Subhanahu wa Ta’ala) said: “They ask thee about the Hour, ‘When will be its appointed time? Wherein art thou (concerned) with the declaration thereof? With thy Lord is the Limit fixed therefor. Thou art but a Warner for such as fear it. The Day they will see it, (it will be) as if they had tarried but a single evening, or (at most till) the following morn!” (Al-Nazi’at 79: 42-46)