Al-Kāfi - Volume 5 > The Case of Prices of Goods
Hadith #3

3- مُحَمَّدُ بْنُ يَحْيَى عَنْ مُحَمَّدِ بْنِ أَحْمَدَ عَنِ الْعَبَّاسِ بْنِ مَعْرُوفٍ عَنِ الْحَجَّالِ عَنْ بَعْضِ أَصْحَابِهِ عَنْ أَبِي حَمْزَةَ الثُّمَالِيِّ عَنْ عَلِيِّ بْنِ الْحُسَيْنِ (عَلَيْهِما السَّلام) قَالَ إِنَّ اللهَ عَزَّ وَجَلَّ وَكَّلَ بِالسِّعْرِ مَلَكاً يُدَبِّرُهُ بِأَمْرِهِ.

3. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn al-‘Abbas ibn Ma’ruf from al-Hajjal from certain persons of his people from abu Hamzah al-Thumaliy who has said the following: “Ali ibn Al-Husayn, ‘Alayhi al-Salam, has said, ‘Allah, most Majestic, most Glorious, has assigned an angel who regulates prices by His command.’”