This is what Ubayy said. The women and the men used to perform ablution together from a single vessel during the time of the Messenger of Allah ﷺ, all dipping into it together.
حدثنا ابن نمير حدثنا عبيد الله
كذا قال أبي كان النساء والرجال يتوضئون على عهد رسول الله ﷺ من إناء واحد ويشرعون فيه جميعا
Its isnad is sahih, despite what appears on its surface to be a mursal transmission. It seems to me that Imam Ahmad did not hear from his teacher Ibn Numayr, after Nafi, the words "from Ibn Umar." The hadith is well known as the hadith of Ibn Umar. That is why Abdullah bin Ahmad's statement, "This is what my father said," confirms that his father did not mention "from Ibn Umar" after Nafi, even though he included the hadith and recorded it in the Musnad of Ibn Umar. Had this narration been mursal and disconnected according to Ahmad, he would not have included it in the Musnad of Ibn Umar.Ahmad had already narrated something similar (5799) from Muhammad bin Ubayd, from Ubaydullah, from Nafi, from Ibn Umar, that men and women used to perform wudu together from a single vessel in the time of the Messenger of Allah ﷺ.Hakim likewise narrated it in Mustadrak (1:152) through Muhammad bin Ubayd and Abu Khalid, both from Ubaydullah, from Nafi, from Ibn Umar, "We, men and women, used to perform wudu and wash our hands in a single vessel, in the time of the Messenger of Allah ﷺ." Hakim said, "This is a sahih hadith meeting the criteria of the two Shaykhs, though they did not record it with this wording." Dhahabi agreed with him.Daraqutni narrated it (p. 20) through Abu Khalid Ahmar, from Ubaydullah, from Nafi, from Ibn Umar, "In the time of the Messenger of Allah ﷺ, a man and a woman would perform wudu from a single vessel." Daraqutni said, "Ayub, Malik, Ibn Jurayj, and others corroborated him."Ayub's narration from Nafi, from Ibn Umar, has already appeared with similar wording at 4481. Malik's narration from Nafi, from Ibn Umar, has already appeared at 5928.We noted in the commentary on 4481 that Abu Dawud narrated it (1:30) through Ayub, from Nafi. We add here that Bukhari narrated it (1:259), as did Nasai (1:23, 24) and Ibn Majah (1:78), all three through Malik, from Nafi, from Ibn Umar.Abu Dawud also narrated it (1:30) through Yahya Qattan, from Ubaydullah, who said, "Nafi told me, from Abdullah bin Umar, who said, 'We and the women used to perform wudu in the time of the Messenger of Allah ﷺ from a single vessel, dipping our hands into it.'"This narration is the closest in wording to the Musnad's narration at this point. It supports the fact that the hadith in this context is the hadith of Ibn Umar, and that Ubaydullah, when he narrated it, mentioned Ibn Umar in his narration. That is why we ruled out the possibility that Imam Ahmad did not hear the name of Ibn Umar after Nafi from his teacher Ibn Numayr.His statement, "They all dip into it together," comes from ishra, meaning to put one's hands in. It is said, "He dipped his hand into the water vessel," meaning he put it into it. From this comes the hadith about wudu, "until he dipped into the upper arm," meaning he brought the water to it, as stated in Lisan Arab.This hadith, and others of similar meaning, is something the foolish people of our time want to seize upon, those who love for indecency to spread among the believers. They want to use it as evidence for the permissibility of a woman uncovering her arms and other parts in front of men, and to reject what Allah and His Messenger commanded regarding a woman's covering and her protection from mixing with men who are not her mahrams.I myself have heard such nonsense from a man with whom the Muslims are afflicted, and with whom Al-Azhar is afflicted, one who claims to be among the scholars. This wretched man wants to be a slave, wanting the Westernized people, the women, and the slaves of women to be pleased with him. They have lied, and this wretched scholar has lied as well.There is nothing in the hadith of Ibn Umar, in its various narrations, that indicates what they want from such worthless speech.Ibn Umar only intends to refute those who claimed that it is disliked to perform wudu or ghusl with water left over by a woman, using this as evidence that the prohibition of that was abrogated. He wanted to clarify that there is nothing wrong with a man and a woman performing wudu together from a single vessel, or performing ghusl together, and that they used to do this in the time of the Messenger of Allah ﷺ, seeing no harm in it.The closest wording to this is Daraqutni's narration, "A man and a woman would perform wudu from a single vessel." So when he says, "We, men and women, used to perform wudu," or "We and the women used to perform wudu," or similar phrases, he does not mean that women mixed with men in one group or in groups, where men would see the arms, upper arms, chests, and necks of women, things that must inevitably be uncovered during wudu. Rather, he means the distribution among households, that is, each man with his own family, in his own house, among his own mahrams.This is self-evident, known necessarily from the religion. That is why Bukhari, in Sahih Bukhari (1:258), titled his chapter for this narration, "Chapter on a man performing wudu with his wife."The hadith of Ibn Umar in this regard is like the hadith of Ayesha, "I and the Messenger of Allah ﷺ used to perform ghusl from a single vessel, our hands going back and forth in it, for janaba." This was narrated by Ahmad and the two Shaykhs, as in Muntaqa number 18.Had these ignorant, foolish people, and this ignorant "reformist" scholar, used their reason, they would have wondered, where in Madinah, in the time of the Messenger of Allah ﷺ, was there a public washing place where men and women would gather together, in the manner they have understood with their brilliant, clever minds?It is well known that they used to draw water from the wells that were in Madinah, men and women alike, and it is well established among the Companions and those who came after them among the Tabiin and their followers, the protected believers, up to our own time, that men should be careful not to look upon any part of a woman's private parts that Allah has commanded to be covered, and that women should be careful not to reveal what Allah has commanded to be covered.We have seen this ourselves in Madinah and among its people, may Allah protect it from the entry of the immorality with which most Muslim lands have been afflicted.