The Excellence of Prayers and Strong Recommendation about it
Al-Kāfi|Volume 2|Book 2|Chapter 1
6ـ أَبُو عَلِيٍّ الأشْعَرِيُّ عَنْ مُحَمَّدِ بْنِ عَبْدِ الْجَبَّارِ عَنِ ابْنِ أَبِي نَجْرَانَ عَنْ سَيْفٍ التَّمَّارِ قَالَ سَمِعْتُ أَبَا عَبْدِ الله (عَلَيهِ السَّلام) يَقُولُ عَلَيْكُمْ بِالدُّعَاءِ فَإِنَّكُمْ لا تَقَرَّبُونَ بِمِثْلِهِ وَلا تَتْرُكُوا صَغِيرَةً لِصِغَرِهَا أَنْ تَدْعُوا بِهَا إِنَّ صَاحِبَ الصِّغَارِ هُوَ صَاحِبُ الْكِبَارِ.
6. Abu Ali al-Ash’ari has narrated from Muhammad ibn ‘Abd al-Jabbar from ibn Abu Najran from Sayf al-Tammar that he heard Abu ‘Abdillah (al-Sadiq) عليه السلام: "Cling to supplication, for you will not be able to draw as close [to Allah] by a means other than this. Do not neglect supplicating for the smallest of things due to its insignificance. Indeed, the one who is turned to for small matters, is also turned to for big matters."
- Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (12/8)
- Ṣaḥīḥ al-Kāfī, vol. 1, p. 136