Tafsir of An-Nazi'at 79:42

"They ask you about the Hour, when is its anchorage?" meaning, when is its establishment—that is, when will Allah the Exalted establish, bring into existence, and fix it? "Al-Mursa" is a noun derived from the verb sara (to be firm/stationary), in the sense of establishing, from which comes "the firm mountains" (al-rawasi). The essence of the interrogative sentence is a question regarding the time of its establishment and existence.

It has been suggested that "al-mursa" may mean the end-point—that is, when is its finality and its place of settlement? Just as the anchorage of a ship is the place where it ends its journey and settles. This is what has been said. However, estimating the question as "when" implies that "al-mursa" is a noun of time (zaman), while the statement "just as the ship..." suggests it is a noun of place (makan). For this reason, it has been argued that the speech relies on metaphor, treating the distant Day as a traveler that cannot be grasped or reached until it settles in a place, thus making the time of its arrival its place of settlement. So, reflect upon this.