And Muhammad ibn Ali ibn Mahbub narrated from Muhammad ibn al-Husayn, from Safwan, from Ishaq:
I (narrator) asked Abu Ibrahim عليه السلام, peace be upon him, about ‘working camels, Is there zakat upon them?’ Imam عليه السلام said: “Yes, there is zakat upon them.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 4, p. 56