عَنْ عُمَرَ بْنِ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَقُولُ: ((مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الْآخِرِ فَلَا يَدْخُلِ الْحَمَّامَ إِلَّا بِإِزَارٍ، مَنْ كَانَتْ تُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الْآخِرِ فَلَا تَدْخُلِ الْحَمَّامَ))
It is narrated from Sayyiduna Umar bin Khattab (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Whoever believes in Allah and the Last Day should not enter the bathhouse without a lower garment (izar), and any woman who believes in Allah and the Last Day should not enter the bathhouse (under any circumstances).