The Times and Conditions in which there is Hope for Acceptance
Al-Kāfi|Volume 2|Book 2|Chapter 13
5ـ عَنْهُ عَنْ أَبِيهِ عَنْ حَمَّادِ بْنِ عِيسَى عَنْ حُسَيْنِ بْنِ الْمُخْتَارِ عَنْ أَبِي بَصِيرٍ عَنْ أَبِي عَبْدِ الله (عَلَيهِ السَّلام) قَالَ إِذَا رَقَّ أَحَدُكُمْ فَلْيَدْعُ فَإِنَّ الْقَلْبَ لا يَرِقُّ حَتَّى يَخْلُصَ.
5. It is narrated from him (Ali ibn Ibrahim) from his father from Hammad ibn ‘Isa from al-Husayn ibn al-Mukhtar from Abu Basir that Abu ‘Abdillah (al-Sadiq عليه السلام said: "When one of you feels tenderness in your heart, let him supplicate, for the heart does not become tender until it is sincere."
- Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (12/36)
- Ṣaḥīḥ al-Kāfī, vol. 1, p. 138