Renewal of Wudoo at each prayer.
The Prophet (saw) said:
“Had it not been difficult for my nation (Muslims), I would have ordered them to perform Wudoo for each prayer, and to use the tooth-stick with each Wudoo.” (Reported by Ahmad)
He (saw) also said:
“If a person performs Wudoo while he is (ritually) pure, the reward for his Wudoo will be ten-fold (i.e. ten hasanat will be recorded for him).” (Reported by Abu Daud, Tirmidhi and Ibn Majah)
On going to sleep:
Al-Bara’ ibn Azib (raa) narrated: the Prophet (saw) said: “Whenever you go to bed perform ablution like the one you perform for prayer, lie on your right side and say: “Allahumma aslamtu wajhi ilayk, wa fawwadtu amri ilayk, wa alja’tu Zahri ilayk, raghbatan wa rahbatan ilayk, la malja’a wala manja minka illa ilayk. Allahumma amantu bikitabikal-ladhi anzalta, wa binabiyikal-ladhi arsalta.” (O Allah! I surrender to You and entrust all my affairs to You, and depend upon You for blessings, both with hope and fear of You. There is no fleeing from You, and there is no place of protection and safety except with You. O Allah! I believe in Your Book (the Qur’an) which You have revealed and in Your Prophet Muhammad (saw) whom you have sent.) Then if you die on that very night, you will die on the religion of pure nature (i.e. Islam). Let the aforesaid words be your last utterance (before sleep).” (Reported by Bukhari)
In case of major ritual impurity (Janabah) if one wants to eat, drink, sleep or practise (with one’s wife) sex again.
Ammar ibn Yasser (raa) said: “Allah’s Messenger (saw) recommended the person who has Janabah to perform Wudoo like the one performed for prayer in case he/she wants to eat, drink or sleep.” (Reported by Ahmad & Tirmidhi)
The Prophet (saw) also said:
“If a person goes to bed with his wife and then intends to have her again, let him perform Wudoo.” (Narrated by all except Bukhari)
Just before the ritual bath for Janabah, and after menstruation and postpartum (childbirth) period.
A’ishah (ra) reported that: “Allah’s Messenger (saw) on taking a bath for Janabah, used to wash his hands, and use his right hand to pour water on his left hand to wash his private parts, then perform Wudoo like that for prayer.” (Agreed upon)
