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:104:7 –

Which mounts directed at the hearts.  

which peers over the hearts, to burn them — the pain of which is much more severe than any other because of the delicate nature ˹of the heart˺.
القرآن:١٠٤:٧ –

الَّتِي تَطَّلِعُ عَلَى الْأَفْئِدَةِ  

{التي تطَّلع} تشرف {على الأفئدة} القلوب فتحرقها وألمها أشد من ألم غيرها للطفها.