ʿUyūn akhbār al-Riḍā
Hadith 4141 - وَبِهذَا الإِسنادِ قالَ: قالَ رَسُولُ اللَّهِ صَلَّى اللهُعَلَيْهِ وَآلِهِ: عَلَيْكُمْ بِحُسنِ الْخُلْقِ فَإِنَّ حُسنَ الخُلقِ الجَنَّةِ لا مَحالَةَ، وَإيّاكُم وَسُوءِ الْخُلْقِ، فَإِنَّ سُوءَ الْخُلْقِ فِي النَّارِ لا مَحالَةَ.
31-41 According to the same documentation, God’s Prophet (S) said, “I advise you to be good-tempered as undoubtedly a good-tempered person will go to Paradise. I admonish you against being bad-tempered, since a bad-tempered person will undoubtedly go to Hell.”