Al-Kāfi
Hadith 7082ـ عَنْهُ عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ مُعَمَّرِ بْنِ خَلادٍ قَالَ سَمِعْتُ أَبَا الْحَسَنِ (عَلَيهِ السَّلام) يَقُولُ إِنَّ لله عِبَاداً فِي الأرْضِ يَسْعَوْنَ فِي حَوَائِجِ النَّاسِ هُمُ الآمِنُونَ يَوْمَ الْقِيَامَةِ وَمَنْ أَدْخَلَ عَلَى مُؤْمِنٍ سُرُوراً فَرَّحَ الله قَلْبَهُ يَوْمَ الْقِيَامَةِ.
2. It is narrated from him (narrator of the Hadith above) from Ahmad ibn Muhammad from Mu’ammar ibn al-Khallad who has said the following: “I heard abu al-Hassan (a.s.) saying, ‘There are servants of Allah on earth who endeavor to help people, these (helping ones) will be secure and safe on the Day of Judgment. Whoever sends joy to the heart of a believer, on the Day of Judgment, Allah will fill his heart with joy.’”