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:40:3 –

The forgiver of sin, acceptor of repentance, severe in punishment, owner of abundance. There is no deity except Him; to Him is the destination.  

Forgiver of sins, for believers, and Accepter of repentance, from them (al-tawb is the verbal noun), Severe in punishment, of disbelievers — in other words, One Who makes it severe for them — One of ˹abundant˺ bounty, bestower of abundant grace — God is eternally possessed of all of these attributes, and so the annexation construction using the derivatives ˹of these attributes˺ is for the purposes of characterisation, as in the case of the last. There is no god except Him; to Him is the journeying, the ˹ultimate˺ return.
القرآن:٤٠:٣ –

غَافِرِ الذَّنْبِ وَقَابِلِ التَّوْبِ شَدِيدِ الْعِقَابِ ذِي الطَّوْلِ ۖ لَا إِلَٰهَ إِلَّا هُوَ ۖ إِلَيْهِ الْمَصِيرُ  

{غافر الذنب} للمؤمنين {وقابل التوب} لهم مصدر {شديد العقاب} للكافرين أي مشدده {ذي الطول} الإنعام الواسع، وهو موصوف على الدوام بكل هذه الصفات، فإضافة المشتق منها للتعريف كالأخيرة {لا إله إلا هو إليه المصير} المرجع.