Narrated by the Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, narrated to me from Abu al-Qasim Ja’far ibn Muhammad, from his father, from Sa’d ibn Abdullah, from Ya’qub ibn Yazid, from Muhammad ibn Abi Umayr, from Umar ibn Udhaynah, from Zurara, from Abu Abdullah عليه السلام, who said: I asked Imam عليه السلام about the ghusl on Friday, and Imam عليه السلام said: 'It is a sunnah in both travel and residence, except if the traveler fears harm from the cold.'"