Concise Quran Commentary
It will only be one blow of the trumpet (the second blowing), and suddenly they will all be looking at the horrors of the Day of Judgement, awaiting what Allah will do with them.
Tafsir for this Ayah
Surah 37 : Ayah 19
Surah 37 : Ayah 19
فَإِنَّمَا هِىَ زَجْرَةٌ وَٰحِدَةٌ فَإِذَا هُمْ يَنظُرُونَ
It will only be a single Blast[4], and at once they will be looking around.