Source: Ahkam wa Masail in the Light of the Qur'an and Hadith, Volume 02
It is considered mustahabb (recommended) to say Bismillah before both Wudu (ablution) and Ghusl Janabah (ritual bath after major impurity). This means that saying it is commendable and preferred, but omitting it does not invalidate the Wudu or Ghusl.
The Hadith states:
"There is no Wudu for the one who does not mention the name of Allah upon it."
(Sunan Abu Dawood, Kitab al-Taharah)
This Hadith is classified as Hasan li-ghayrihi (sound due to supporting chains), indicating that mentioning Allah’s name during Wudu is recommended.
At the beginning of Wudu or Ghusl, saying "Bismillah" is sufficient. However, if one says "Bismillah al-Rahman al-Rahim", it is also permissible and valid, as it too includes the mention of Allah's name. There is no prohibition against using the full phrase.
➊ It is recommended (mustahabb) to say Bismillah at the beginning of Wudu or Ghusl Janabah.
➋ Both "Bismillah" and "Bismillah al-Rahman al-Rahim" are acceptable, as both constitute the remembrance of Allah.
✿ Ruling on Reciting Bismillah Before Wudu and Ghusl Janabah
It is considered mustahabb (recommended) to say Bismillah before both Wudu (ablution) and Ghusl Janabah (ritual bath after major impurity). This means that saying it is commendable and preferred, but omitting it does not invalidate the Wudu or Ghusl.
The Hadith states:
"There is no Wudu for the one who does not mention the name of Allah upon it."
(Sunan Abu Dawood, Kitab al-Taharah)
This Hadith is classified as Hasan li-ghayrihi (sound due to supporting chains), indicating that mentioning Allah’s name during Wudu is recommended.
➊ Bismillah or Bismillah al-Rahman al-Rahim?
At the beginning of Wudu or Ghusl, saying "Bismillah" is sufficient. However, if one says "Bismillah al-Rahman al-Rahim", it is also permissible and valid, as it too includes the mention of Allah's name. There is no prohibition against using the full phrase.
❖ Summary
➊ It is recommended (mustahabb) to say Bismillah at the beginning of Wudu or Ghusl Janabah.
➋ Both "Bismillah" and "Bismillah al-Rahman al-Rahim" are acceptable, as both constitute the remembrance of Allah.