Al-wudu’ is either obligatory or recommended.
a- There are three things for which al-wudu is obligatory.
1- As-Salah (Prayers)
Allah (exalted be He) said: “O you who believe, when you intend to offer As-Salah (prayers), wash your faces and your hands up to the elbows, rub your heads, and wash your feet up to (and including) the ankles.” (Al-Ma’idan:6).
2- Circumambulation of Ka’bah.
This is because the Prophet ﷺ said to a menstruating woman: “Do not perform Tawaf until you have taken a purificatory bath.” [ narrated by Al-Bukhari.]
3- Touching the Noble Qur’an:
Allah the most Exalted says: “None touch it (The Noble Qur’an) except the purified”(Waqiah:79)
The Prophet ﷺ said: “My nation will come forth on the day of judgment like ‘Ghurrah Muhajjaleen’ (horses with white forelocks and white feet)[ Al-Ghurru: is the white patch on the forehead of the horse. Muhajjaleen: are horses with white feet. At-Tahjeel: White patches on their limbs. This refers to the light on the Day of Judgment that will be on the parts of the body that used to be washed during al-wudu’.] as a result of making Al-wudu’. So any of you (who is) capable of lengthening his ghurrah (places of light) should do so.” [ agreed upon.]
Putting a Sutrah (barrier placed in front of a person praying) is a necessity for both men and women. It is impermissible for anyone to pass in front of a person offering Salah, or between them and their Sutrah, whether the person praying is a man or a woman, and whether the passing person is a man or woman. But, if the passing person is a woman, her passage would interrupt the Salah of the person she passes in front of, or between them and their Sutrah, except in Al-Masjid Al-Haram (the Sacred Mosque in Makkah) where she would be excused for the difficulty of preventing that from taking place. Allah (Glorified and Exalted be He) says: So keep your duty to Allâh and fear Him as much as you can and ...and He has not laid upon you in religion any hardship May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.
1. Delaying a ghusl until the time of a prayer is about to leave.
2. For a female not to pray an obligatory prayer after her menstrual cycle stops.
For example, her cylcle stopped before the period of zhur was over and the time ramaining for that prayer was enough to pray one raka’a of prayer. In this case it is obligatory on her to take a bath and pray zhur. The Prophet ﷺ said: “He who performs a raka’a of Subh prayer before the sun rises, has met (the time for) Salatul Subh. And he who performs a raka’a of Asr prayer before sunset, has met (the time for) Salatul ‘Asr.” [ agreed upon],