Nasai

161. Commentary:

➊ It is understood from this that ablution (wudu) is nullified by sleep; this is why the mention of the water vessel comes after waking up.

➋ Ablution is nullified by sleep because, in this state, the likelihood of air being released from the body increases, and the sleeper is unaware of it. Similarly, if drowsiness becomes so overwhelming that consciousness and awareness are completely lost, this too is considered sleep, and absolute sleep nullifies ablution, regardless of the position in which it occurs, because there are hadiths regarding the nullification of ablution upon absolute sleep. However, if the senses remain intact during sleep and consciousness is alive, what we call "drowsiness" in our language, then in whatever state it occurs, ablution is not nullified. And Allah knows best.

442. Commentary: For clarification, see Sunan an-Nasa'i Hadith: 161, 162 and their benefits and issues.

1. Commentary:
➊ The purpose of Imam al-Nasa’i rahimahullah in mentioning this hadith appears to be that before placing the hands into the vessel for ablution (wudu), one should wash them three times, and then begin the ablution.
➋ From this, the ruling is also derived that the water used for ablution should not be impure, as has been explicitly stated in other ahadith. See: [صحيح البخاري، الوضوء، حدیث : 185، 186 و صحیح مسلم، الطھارة، حدیث : 235]
➌ In this hadith, the washing of hands after waking from sleep at night is mentioned, but this reasoning is general, and the same situation can occur after sleep during the day as well. Therefore, due to the generality of the reasoning, it is necessary to wash the hands after any sleep.
➍ The purpose of ablution (wudu) is not only legal (shar‘i) purification but also physical cleanliness.
➎ For impurities that are not visible, such as if urine dries or something doubtful comes into contact, it is better to wash them three times; in this way, it will become pure. However, if the impurity is visible or perceptible, then its removal is necessary.

Benefit:

........ In the state of sleep, it is possible that the hand may have touched the private part, therefore it should be washed, rather, it should be washed three times.

[صحيح مسلم: 278]

And just as this concern exists with sleep at night, similarly, there is also the possibility of it occurring during sleep in the day.

English Commentary:
1:
The restriction to vessels excludes ponds, pools, canals, etc. from this ruling, because their water is more than two qullahs (large containers), thus after waking from sleep, it is permissible to insert the hand into them.

2:
From this it is understood that Imam Shafi'i has interpreted the hadith of this chapter as being recommended (mustahabb), and this is also the view of the majority (jumhur). Ahmad and Ishaq ibn Rahwayh have interpreted it as obligatory (wajib), but Ahmad has restricted it to sleep at night, while Ishaq ibn Rahwayh has kept it general. The author of Tuhfat al-Ahwadhi has considered the view of Ishaq ibn Rahwayh to be the stronger opinion, and caution lies in this. The restriction to "night" is only because a person generally sleeps at night. Also, in the narrations of the two Sahihs (Sahih al-Bukhari and Sahih Muslim), instead of "min al-layl" ("from the night"), it is "min nawmihi" ("from his sleep"), so this applies generally to every sleep, whether by night or by day.

Benefits and Issues:
➊ This ruling applies to all types of vessels; however, rivers and large ponds or pools are exempt from this ruling, and it is permissible to insert the hand into them. Hafiz Ibn Hajar rahimahullah has also expressed this same opinion in Fath al-Bari. According to the majority of scholars, this ruling is based on recommendation (istihbab), but Imam Ahmad rahimahullah considers it obligatory (wajib). However, the opinion of the majority is closer to correctness. Nevertheless, if one is certain that his hand has been contaminated with impurity or filth, then it is necessary to wash the hand before inserting it into the vessel.

➋ In the aforementioned hadith, only the night is mentioned because the likelihood of coming into contact with impurity is greater at night compared to the day. In any case, the mentioned ruling is the same for both day and night; therefore, if one wakes up after sleeping during the day, one should also act upon this instruction.

Commentary:
(1)
The ruling for night and day is the same.
The word "night" is mentioned in the hadith because a person generally sleeps more at night.

(2)
The wisdom behind washing the hands before dipping them into water is that, during sleep, a person is unaware of his actions and movements. Therefore, it is possible that the hands may have touched the nose or other private parts, or, in the case of sleeping on the ground, may have come into contact with soil, etc. Thus, cleanliness and purification require that upon waking from sleep, the hands should be washed.

(3)
The command to wash two or three times is so that the hands are thoroughly cleaned and no doubt remains. Therefore, if one is certain of cleanliness after washing once, that is sufficient.

(4)
Some scholars have deduced from the word "vessel" that this ruling applies to all types of vessels; however, rivers, ponds, and pools are exempt from this ruling.
The reason for this could also be that the water in ponds and pools is abundant.
A small amount of impurity mixing into it does not render it impure, and in the aforementioned situation, even this impurity is not certain, but merely a possibility.

Benefit:
From this hadith, it is understood that whoever wakes up from sleep, whether during the day or night, should wash his hands thoroughly before putting them into a vessel. It is also understood from this that the human being is weak, and it is also evident that the human being does not possess knowledge of the unseen. Furthermore, it is established from this that touching the private parts breaks ablution (wudu).