Ahmad ibn Muhammad, from Muhammad ibn Yahya, from Ghiyath ibn Ibrahim, from Imam Ja’far عليه السلام, from his father عليه السلام, peace be upon them, who said:
Imam al-Sadiq عليه السلام said: “He (Imam al-Baqir عليه السلام) would shorten the prayer when he departed from Kufah, at the first prayer that became due upon Him عليه السلام.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 3, p. 258