Hasan Ibn Yusuf Ibn Mutahhar Al-Hilli writes:

المشهور بين علمائنا أن غسل الجمعة مستحب وليس بواجب وقال ابن بابويه إنه واجب على الرجال والنساء، في السفر والحضر، إلا أنه رخص للنساء في السفر لقلة الماء وفي موضع آخر من كتابه إن غسل يوم الجمعة سنة واجبة والوجه الأول لنا أصالة براءة الذمة مع عدم المعارض يقتضي ما قلناه وما ذكرناه من حديث سعد احتج ابن بابويه بما رواه سماعة، عن الصادق عليه السلام قال: سألته عن غسل الجمعة؟ فقال: واجب في السفر، والحضر إلا أنه رخص للنساء في السفر لقلة الماء وما رواه عبد الله بن المغيرة في الحسن، عن أبي الحسن الرضا عليه السلام قال: سألته عن الغسل في يوم الجمعة، فقال: واجب على كل ذكر وأنثى من عبد أو حر ومثله ما رواه محمد بن عبد الله، عن الرضا عليه السلام والجواب: ما تقدم مرارا من أن المراد به الاستحباب المؤكد، ويؤيده ما رواه علي بن يقطين في الحسن، قال: سألت أبا الحسن عليه السلام عن الغسل في الجمعة، والأضحى، والفطر قال: سنة وليس بفريضة وفي الصحيح عن زرارة، عن أبي عبد الله عليه السلام قال: سألته عن غسل الجمعة، فقال سنة في السفر والحضر إلا أن يخاف المسافر على نفسه القر وعن القاسم، عن علي، قال: سألت أبا عبد الله عليه السلام عن غسل العيدين أواجب هو؟ فقال: هو سنة، قلت: فالجمعة؟ قال: هو سنة

,,It is widely believed among the knowledgeable among us, that the washing (Ghusl) on Friday is desirable (Mustahab) and not obligatory and Muhammad As-Saduq says: “It is established (Wajib) for the men and women both while traveling and outside of it, except that the women are exempted from it while traveling due to lack of water.” In another place in his book he writes: “The washing on Friday is a custom (Sunnah) that is established (Wajib).” The first point of view that arises for us is the original exemption in the absence of a contradiction, which demands what we said and mentioned in traditions of Sa’d Ibn Abdillah. As-Saduq argued with the tradition of Sama’ah in which he asked Ja’far As-Sadiq (a.): “What is it about the washing (ghusl) on Friday?” He said: ,,It is established (Wajib) both when traveling and outside of it, with the exception that women are exempt when traveling due to lack of water.” As well as with what is transmitted from Abdullah Ibn Mughirah which is good (hasan) wherein he asked Ali Ar-Rida (a.): ,,What about the washing (ghusl) on Friday?” He said: “It is established (wajib) for every man and woman among the slaves and the free.” As well as similar to this what Muhammad Ibn Abdillah reported from Ali Ar-Rida (a.). The answer to this consists, in what has often preceded: ,,By this is meant, that it is extremely desirable (Mustahab).” This corroborates what is transmitted from Ali Ibn Yaqtin which is good (hasan),wherein he asked Ali Ar-Rida (a.): ,,What is it about the washing (Ghusl) on Friday and at the Feast of Sacrifice and breaking of the fast?” He said: ,,It is a custom (Sunnah) and not an obligation (Fard).” It is authentically (Sahih) transmitted from Zurarah that he asked Ja’far As-Sadiq (a.): ,,What is it about the washing (Ghusl) on Friday?” He said: ,,It is a custom (Sunnah) both when traveling and staying, unless the traveler fears for himself because of the cold.” Al-Qasim reported Ali as asking Ja’far As-Sadiq (a.): ,,What is it about the washing (Ghusl) on the two feast days? Is it established (wajib)?” He said: ,,It is a custom (Sunnah).” I said: ,,What about the one on Friday?” He said: ,,It is a custom (Sunnah).”  [Mukhtalaf-ush-Shi’ah, Volume 1 Page 318 – 319]