Ali ibn Ibrahim, from his father, from Al-Nawfali, from Al-Sakuni, from Abu Abdullah عليه السلام:
Imam عليه السلام said: “The Prophet صلى الله عليه وعلى آله وسلم forbade that the grave be dug deeper than three cubits.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 478
