Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:69:50 –

And indeed, it will be ˹a cause of˺ regret upon the disbelievers.  

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.
القرآن:٦٩:٥٠ –

وَإِنَّهُ لَحَسْرَةٌ عَلَى الْكَافِرِينَ  

{وإنه} أي القرآن {لحسرة على الكافرين} إذا رأوا ثواب المصدقين وعقاب المكذبين به.