Surah Maryam 19:39

وَأَنذِرْهُمْ يَوْمَ ٱلْحَسْرَةِ إِذْ قُضِىَ ٱلْأَمْرُ وَهُمْ فِى غَفْلَةٍ وَهُمْ لَا يُؤْمِنُونَ

And warn them, [O Muḥammad], of the Day of Regret, when the matter will be concluded; and [yet], they are in [a state of] heedlessness, and they do not believe.

Translation: Saheeh International

Tafsir

And warn them threaten O Muhammad (s) the disbelievers of Mecca of the Day of Regret namely the Day of Resurrection on which the sinner will regret not having been virtuous in the life of this world when the matter will be decided for them thereupon that they be chastised while they in this world are yet heedless of …

Excerpt from Tafsir al-Jalalayn, commentary on 19:39, via Quran.com. The reader has the full commentary and 9 more tafsirs.