Muhammad ibn Ahmad ibn Yahya, from some of our companions, who raised it to Abu Abdillah عليه السلام, peace be upon him, who said:
Imam عليه السلام said: “Whoever prays four rakahs during his travel, then I am free of him before Allah سبحانه وتعالى.” – meaning does not shorten his prayer.
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 4, p. 284