Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
It is preferred to have wudu for the following actions: while mentioning the name of Allah, going to sleep, to remove a sexual impurity, before performing ghusl, before eating food touched by fire, and renewing the wudu for every prayer.
In his famous work, Fiqh As-Sunnah, Sheikh Sayyid Sabiq, elaborates on the subject as follows:
It is preferred to have wudu for the following actions:
- While mentioning the name of Allah
Al-Muhajir ibn Qunfuzh related that he greeted the Prophet (peace be upon him) but that the latter did not return his salutation until he had made wudu: “There is nothing that prevented me from responding to you except that I do not like to mention the name of Allah unless I am in a state of purity.”
Said Qatadah, “Because of this, al-Hassan hated to recite the Quran or mention Allah’s name unless he had performed wudu. (Ahmad, Abu Dawud, an-Nasa’i and Ibn Majah)
Raeported Abu Juhaim ibn al-Harith, “The Prophet (peace be upon him) met a person at the well of Jaml, who greeted him, but he did not return his greeting until he had wiped his face and hands.” (Ahmad, al-Bukhari, Muslim, Abu Dawud and an-Nasa’i) This action was one of preference, not of obligation.
Mentioning the name of Allah is permissible for the one who is in a state of purity, one who has a minor impurity, a person in post-sex impurity, or one who is standing, sitting, and so on.
Aishah said, “The Messenger of Allah used to remember Allah at all times.” (Related by “the five,” except for an-Nasa’i)
Al-Bukhari recorded it in mu`alliq form.) `Ali reported, “The Messenger of Allah would come from relieving himself, recite to us and eat meat with us. Nothing would stop him from the Qur’an except post-sex impurity.” (Related by “the five.” At-Tirmidhi and Ibn as-Sakin categorized it as sahih)
- Going to sleep
Al-Barra’ ibn `Aazib reported that the Messenger of Allah (peace be upon him) said, “When you go to your bed, perform wudu, lie on your right side and then say, ‘O Allah, I submit my soul to You, and I turn my face to You. I entrust my affairs to You. I retreat unto You for protection with hope and fear in You. There is no resort and no savior but You. I affirm my faith in Your books which You revealed and in Your prophets you sent.’ If you die during that night, you will be along the natural path. Make it your final statement (of the night). He reported that he repeated this supplication to the Prophet (peace be upon him) and he said, “…and Your messengers.” The Prophet interjected, “No,… ‘and the prophets You sent.” (Ahmad, al-Bukhari, and at-Tirmidhi)
This also applies to one who is in post-sex impurity . Ibn `Umar asked the Prophet, “O Messenger of Allah, can one of us sleep while he is in post-sex impurity?” The Prophet answered, “Yes, if he makes wudu.” Aishah reported, “When the Prophet (peace be upon him) wanted to sleep in a state of post-sex impurity, he would wash his private parts and perform wudu.” (Related by “the group”)
- To remove a sexual impurity
If a person in a state of post-sex impurity wants to eat, drink or have intercourse again, he should perform wudu.
Aishah said, “When the Prophet (peace be upon him) was in a state of impurity because of intercourse and wanted to eat or sleep, he would perform wudu.” ‘Ammar ibn Yasar reported that the Prophet permitted a person in post-sex impurity to eat, drink or sleep if he performed wudu first. (Related by Ahmad and at-Tirmidhi, who classified it as sahih.)
Abu Sa`eed reported that the Prophet (peace be upon him) said, “If one has intercourse with his wife and wants to repeat the act, he should perform wudu.” (Related by “the group,” except for al-Bukhari. Ibn Khuzaimah, Ibn Hibban and al-Hakim recorded it with the addition, “It makes the return more vivacious.”)
- Before performing ghusl
It is preferred to perform wudu before ghusl regardless of whether that particular ghusl was an obligatory or a preferred act. Aishah said, “When the Messenger of Allah (peace be upon him) performed post-sex ghusl, he would begin by washing his hands and then pour water from his right hand to his left and wash his private parts. He would then perform wudu..” (Related by “the group.”)
- Before eating food touched by fire
Ibrahim ibn Abdullah ibn Qarizh said, “I passed by Abu Hurairah while he was performing wudu and he said, ‘Do you know why I am making wudu? It is because I ate some yoghurt dried over a fire, for I heard the Messenger of Allah say, ‘Perform wudu before eating food touched by fire.” (Related by Ahmad, Muslim and “the four.”)
Aishah related that the Prophet (peace be upon him) said, “Perform wudu from whatever touches fire.” (Related by Ahmad, Muslim, an-Nasa’i and Ibn Majah) This order is one of preference as the following hadith makes clear: ‘Amr ibn Umayyah azh-Zhamari said, “I saw the Messenger of Allah (peace be upon him) cutting a piece of a sheep’s shoulder and eating it. He was then called to prayer. He put the knife down, prayed, and did not perform another wudu.” (Al-Bukhari and Muslim)
- Renewing the wudu for every prayer
Buraidah said, “The Prophet (peace be upon him) made wudu for every prayer. On the day of the conquest of Makkah, he made wudu, wiped over his socks and prayed a number of times with just one wudu. ‘Umar said to him, ‘O Messenger of Allah, you did something that you have not done (before).’ He answered, ‘I did it on purpose, ‘Umar.”‘ (Related by Ahmad, Muslim and others)
Anas ibn Malik said, “The Prophet (peace be upon him) used to make wudu for every prayer.” He was asked, “And what did you people use to do?” Malik said, “We prayed the prayers with one wudu unless we nullified it.” (Related by Ahmad and al-Bukhari)
Abu Hurairah reported that the Prophet said, “Were it not to be a hardship on my people, I would order them to make wudu for every prayer.” (Related by Ahmad with a hasan chain)
Ibn ‘Umar reported that the Prophet (peace be upon him) said, “Whoever makes wudu while he is already in a state of purity will have ten good deeds written for him.” (Abu Dawud, at-Tirmidhi, and Ibn Majah)
Almighty Allah knows best.