Answer
✅Answer:
1️⃣ Zurarah ibn A'yan said: I asked Abu Ja'far and Abu 'Abdillah (peace be upon them both) what invalidates wudu? They said: 'What comes out from your two lower ends, from the anus and the penis: feces, urine, semen, or gas. And sleep that takes away the mind. And every sleep is disliked (causes the invalidation of wudu) except for sleep in which you can hear the sound!'
📚 Tahdhib, vol. 1, p. 9
Zurarah said: I said to Imam Baqir and Imam Sadiq (peace be upon them both): 'What breaks the wudu?' They said: 'What comes out from your two lower ends, from the anus and the penis: feces, urine, or semen, or gas, and sleep that takes away the mind. And every sleep is disliked (causes the invalidation of wudu), except for sleep in which you can hear the sound!'
2️⃣ From Zurarah, he said: I said to him: 'A person sleeps while he has wudu. Do one or two nods obligate him to perform wudu?' He said: 'O Zurarah! Sometimes the eye sleeps but the heart and ear do not. So when the eye, ear, and heart sleep, wudu becomes obligatory.' I said: 'What if something moves next to him and he does not notice it?' He said: 'No, not until he is certain that he has slept, so that a clear matter comes from that. Otherwise, he is certain of his wudu, and certainty is never invalidated by doubt, but rather it is invalidated by another certainty.'
📚 Tahdhib, vol. 1, p. 8
Zurarah said: I said to (the Imam, peace be upon him): 'A person sleeps while he has wudu. Does one or two head nods during a nap obligate him to perform wudu?' The Imam said: 'O Zurarah! Sometimes the eye sleeps but the heart and ear do not. So when the eye, ear, and heart sleep, wudu becomes obligatory.'
I said: 'What if something moves next to him but he doesn't notice it?' The Imam said: 'No (wudu is not obligatory) until he is certain that he has fallen asleep, so that a clear matter comes from that. Otherwise, he is certain of his wudu, and certainty is never invalidated by doubt, but rather it is broken by another certainty!'
3 عن أبي عبداللَّه قال: أُذُنَان و عَيْنَان تَنَامُ الْعَيْنَان و لَا تَنَامُ الْأُذُنَانِ و ذَلِكَ لَا يَنْقُضُ الْوُضُوءَ فَإِذَا نَامَت الْعَيْنَان و الْأُذُنَان انْتَقَضَ الْوُضوء
📚 Al-Kafi, vol. 3, p. 37
Imam Sadiq (peace be upon him) said: 'There are two ears and two eyes! (Sometimes) the two eyes sleep but the two ears do not, and such a state does not break the wudu. So when the two eyes and the two ears fall asleep, the wudu is broken!'
4 علي بن جعفر عن أخيه موسى بن جعفر قال: سَأَلْتُهُ عَنْ رَجُلٍ يَتَّكِئُ في الْمَسْجِدِ فلا يَدْرِي نامَ أَمْ لا هَل عَلَيْهِ وُضُوءٌ قال إِذَا شَكَّ فَلَيْسَ عَلَيْه وُضُوء
📚 Qurb al-Isnad, p. 83
'Ali ibn Ja'far said: 'I asked Musa ibn Ja'far (peace be upon him) about a person who leans in the mosque and does not know whether he has fallen asleep or not. Is wudu obligatory upon him?' The Imam said: 'If he doubts, wudu is not obligatory upon him!'
5️⃣ From Abi al-Sabah al-Kinani from Abi 'Abdillah, he said: 'I asked him about a man who nods during prayer.' He said: 'If he cannot guard against an impurity (or is unaware if one occurs), then he must perform wudu and repeat the prayer. But if he is certain that no impurity has occurred, there is no wudu or repetition upon him.'
📚 Tahdhib, vol. 1, p. 7
Abu al-Sabah al-Kinani said: I asked Imam Sadiq (peace be upon him) about a person whose head moves during prayer due to nodding off. The Imam said: 'If it is to the extent that if an impurity were to be emitted from him, he would not be able to hold it (or would not notice it and would not be able to prevent it), then wudu and repeating the prayer are obligatory upon him. And if he is certain that no impurity (i.e., gas) has been emitted from him, then wudu and repeating the prayer are not obligatory upon him!'
6 عبدالحميد بن عواض عن أبي عبداللَّه قال سَمِعْتُهُ يَقُولُ مَنْ نَامَ وَ هُوَ رَاكِعٌ أَوْ سَاجِدٌ أَوْ مَاشٍ عَلَى أَيِّ الْحَالاتِ فَعَلَيْهِ الْوُضُوء
📚 Tahdhib, vol. 1, p. 6
Abdul Hamid said: I heard Imam Sadiq (peace be upon him) saying: 'Whoever falls asleep while bowing, prostrating, walking, or in any state, it is obligatory upon him to perform wudu!'
7️⃣ Muhammad ibn 'Ubaydullah and 'Abdullah ibn al-Mughirah said: We asked Imam Reza (peace be upon him) about a man who sleeps on his mount. He said: 'If the sleep takes away the mind (awareness and consciousness), then he must repeat the wudu.'
📚 Tahdhib, vol. 1, p. 6
'Abdullah ibn al-Mughirah and Muhammad ibn 'Ubaydullah said: We asked Imam Reza (peace be upon him) about a person who falls asleep on his mount. The Imam said: 'If the sleep takes away the mind (awareness and consciousness), then he must repeat the wudu.'
8️⃣ 'Ali (peace be upon him) said: 'When sleep is mixed with the heart (awareness and intellect), wudu becomes obligatory!'
📚 Khisal, 619
✅So, sleep is one of the things that invalidates wudu, and its criterion is the sleeping of the eyes along with the ears (meaning the ears also do not hear), or the mixing of sleep with the heart, or the taking away of awareness and consciousness by sleep, or the simultaneous sleeping of the eyes, ears, and heart, and similar states. Cases that do not reach this level do not cause the wudu to be broken. If a person experiences sleep with the above criteria, his wudu is invalidated, and if such sleep occurs during prayer, in addition to wudu, the prayer must also be repeated.