Al-Kāfi - Volume 1 > Chapter on the minimum degree of knowledge of the existence of Allah
Hadith #3

3ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ مُحَمَّدِ بْنِ الْحُسَيْنِ عَنِ الْحَسَنِ بْنِ عَلِيِّ بْنِ يُوسُفَ بْنِ بَقَّاحٍ عَنْ سَيْفِ بْنِ عَمِيرَةَ عَنْ إِبْرَاهِيمَ بْنِ عُمَرَ قَالَ سَمِعْتُ أَبَا عَبْدِ الله (عَلَيْهِ السَّلام) يَقُولُ إِنَّ أَمْرَ الله كُلَّهُ عَجِيبٌ إِلا أَنَّهُ قَدِ احْتَجَّ عَلَيْكُمْ بِمَا قَدْ عَرَّفَكُمْ مِنْ نَفْسِهِ.

3. Muhammad ibn Yahya has narrated from Muhammad ibn al-Hassan from al-Hassan ibn Ali ibn Yusuf ibn Baqqah from Sayf ibn ‘Umayra from Ibrahim ibn ‘Umar who has said the following. Imam abu ’Abdallah (a.s.) has said, “The issue about Allah is totally extraordinary. Notice that He has presented to you His arguments in proof of His existence by means of that much of facts about His own self that He has made known to you.”