How authentic are the hadiths which speak of the virtue of doing wudu before going to sleep?
Question

Doing wudu before going to sleep: I received a hadith on my cell phone and I want to ascertain whether it is authentic: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Whoever does wudu before going to sleep, an angel will sleep alongside him, and every time he moves, the angel will say: O Allah, forgive him.” [The message then said:] Spread this hadith and make it for the sake of Allah in the balance of your good deeds.
Praise be to Allah.The hadith with the wording mentioned by the questioner is not to be found in any of the reliable compilations of hadith. However, it seems that the meaning of the hadith has been transmitted, as there are two hadiths with similar meanings which refer to what is mentioned in it.
The first of these hadiths is: “Whoever spends the night in a state of purity, an angel will spend the night under the cover, and he will not wake up but the angel will say: O Allah forgive Your slave So-and-so, for he has spent the night in a state of purity.”
This hadith was narrated by Imam `Abdullah ibn al-Mubarak in az-Zuhd, 64, via al-Hasan ibn Dhakwan from Sulayman al-Ahwal, from `Ata’, from Ibn `Umar, from the Prophet (blessings and peace of Allah be upon him)… And Ibn Hibban narrated it via Ibn al-Mubarak in his Sahih, 1051, and elsewhere.
This is a weak (da`if) isnad. Al-Hasan ibn Dhakwan was classed as weak by Imam Ahmad, Ibn Ma`in and others.
See: Mizan al-I`tidal, 1/489.
But there is a corroborating report which was narrated by at-Tabarani in al-Mu`jam al-Kabir (13620) and others: Isma`il ibn `Ayyash narrated to us, from al-`Abbas ibn `Utbah, from `Ata’ ibn Abi Rabah, from Ibn `Umar (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said: “Purify these bodies and Allah will purify you, for there is no one who spends the night in a state of purity but an angel will remain with him all night under the cover, and he will not turn over at any time in the night but the angel will say: O Allah forgive Your slave, for he has spent the night in a state of purity.”
Al-`Aqili said: Isma`il ibn `Ayyash narrated from `Abbas ibn `Utbah ibn `Ata’; his hadith is not authentic. And he quoted from him the hadith referred to above, then he said: This was narrated with a different isnad, an isnad that is also flimsy [layyin].
End quote from ad-Du`afa’ al-Kabir, 3/361-362.
Some of the scholars are of the view that the hadith is sound when corroborating reports are taken into account.
See: al-Mundhiri: at-Targhib wat-Tarhib, 1/231; al-Haythami: Majma` az-Zawa’id, 1/226; al-Albani: as-Silsilah as-Sahihah, no. 2539.
At-Tabarani also narrated a similar report in al-Awsat, 5087 from Ibn `Abbas (may Allah be pleased with him), but none of its isnads are without issues; however, they may strengthen one another, therefore al-Albani deemed it to be sound because of corroborating reports. Sahih at-Targhib, 599.
The word translated here as cover refers to anything that covers a person’s body, such as clothing and the like.
The idea of doing wudu before going to sleep is proven in the authentic Sunnah. See question no. 12782.
And Allah knows best.