Al-Kāfi - Volume 1 > Chapter on Contingency of the Universe and Proof of the Existence of its Creator
Hadith #6

6ـ مُحَمَّدُ بْنُ يَعْقُوبَ قَالَ حَدَّثَنِي عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ الْبَرْقِيِّ عَنْ أَبِيهِ عَنْ عَلِيِّ بْنِ النُّعْمَانِ عَنِ ابْنِ مُسْكَانَ عَنْ دَاوُدَ بْنِ فَرْقَدٍ عَنْ أَبِي سَعِيدٍ الزُّهْرِيِّ عَنْ ابي جعفر (عَلَيْهِ السَّلام) قَالَ كَفَى لاولِي الالْبَابِ بِخَلْقِ الرَّبِّ الْمُسَخِّرِ وَمُلْكِ الرَّبِّ الْقَاهِرِ وَجَلالِ الرَّبِّ الظَّاهِرِ وَنُورِ الرَّبِّ الْبَاهِرِ وَبُرْهَانِ الرَّبِّ الصَّادِقِ وَمَا أَنْطَقَ بِهِ أَلْسُنَ الْعِبَادِ وَمَا أَرْسَلَ بِهِ الرُّسُلَ وَمَا أَنْزَلَ عَلَى الْعِبَادِ دَلِيلاً عَلَى الرَّبِّ.

6. Muhammad ibn Ya‘qub has said that a number of our people have narrated from Ahmad ibn Muhammad al-Barqi from his father, from Ali ibn al-Ni‘man, from ibn Maskan, from Dawud ibn Farqad from abu Sa‘id al-Zuhri from Imam abu Ja‘far (a.s.) who said the following. “For the people of understanding as proof of the existence of the Allah it is enough that He has created all things and has kept them full under His control. It is enough proof that He is the Most powerful king. It is enough proof that His Majesty is manifest everywhere. That His light is the Most bright that His testimony is the Most truthful. There is enough proof of His existence in what the people speak and what the messengers have brought and what he has revealed to people as proof of His Own existence.”