The Day they will hear the blast [of the Horn] in truth. (50:42)

Almuntakhab Fi Tafsir Alquran Alkarim

This is the Day when all shall hear the exploding annunciation of the matter of fact so announced; this is the Day of Resurrection

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(50:42) the Day when they shall hear the Blast in truth. That will be the Day (for the dead) to come forth. *53

The Day they will hear the blast [of the Horn] in truth. meaning

*53) The words yasm'aun-as-saihata bil haqq-i can have two meanings: (1) That alI the people will be hearing the cry of the right Command; and (2) that they will be hearing the cry rightly. In the first case the sentence will mean that the people will be hearing the same right Command with their cars, which they were not inclined to accept in the world, which they had persistently refused to believe, and mocked the Prophets who had brought it. In the second case it will mean that they will certainly hear this cry, and they will realize that it is no fancy but indeed the Cry of Resurrection; they will be left with no doubt that the Day of Resurrection of which they had been forewarned had arrived and the Cry that was being raised was of the same.
 

The Day they will hear the blast [of the Horn] in truth. meaning in Urdu

جس دن سب لوگ آوازۂ حشر کو ٹھیک ٹھیک سن رہے ہوں گے، وہ زمین سے مُردوں کے نکلنے کا دن ہو گا