Surah Al-Haqqah 69:50

وَإِنَّهُۥ لَحَسْرَةٌ عَلَى ٱلْكَـٰفِرِينَ

And indeed, it will be [a cause of] regret upon the disbelievers.

Translation: Saheeh International

Tafsir

And assuredly it that is the Qur’ān is a cause of anguish for the disbelievers when they see the reward of those who affirmed its truth and the punishment of those who denied it.

Excerpt from Tafsir al-Jalalayn, commentary on 69:50, via Quran.com. The reader has the full commentary and 9 more tafsirs.