Sayyidah Aishah (may Allah be pleased with her) says: When the Messenger of Allah (peace and blessings be upon him) took the ritual bath for janabah (major impurity), he would first wash his hands, then perform the ablution of prayer, then put his fingers into the water and run them through the roots of his hair, then take three handfuls of water with his hand and pour them over his head, then pour water over his whole body.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 823
Sayyidah Aishah (may Allah be pleased with her) says: When the Messenger of Allah (peace and blessings be upon him) took the ritual bath for janabah (major impurity), he would wash his hands and perform ablution as for prayer, then run his hands through his hair; when he (peace and blessings be upon him) was confident that he had moistened his skin, he would pour water over it three times, then wash his whole body. Sayyidah Aishah (may Allah be pleased with her) says: The Messenger of Allah (peace and blessings be upon him) and I used to bathe together from a single vessel, both of us scooping water from it together.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 824
Sayyidah Aishah (may Allah be pleased with her) says: The Messenger of Allah (peace and blessings be upon him) would perform ablution (when bathing) from janabah (major impurity), then put his right hand into the water, then run it through the right side of his head, working it in among the hair; then he would do the same to the left side with his left hand, until the water reached the skin. Then he would pour water over his head three times.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 825
Sayyiduna Ali (may Allah be pleased with him) says: I heard the Prophet (peace and blessings be upon him) say: "Whoever leaves even a hair's breadth of his body untouched by water in (the bath for) janabah (major impurity) will be dealt with in such and such a way in the Fire."
Sayyiduna Ali (may Allah be pleased with him) says: Because of that I have made an enemy of my head. Ubaydullah states in his narration that Sayyiduna Ali (may Allah be pleased with him) used to cut his hair down to the roots.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 826
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Under every hair there is janabah (impurity), so wash the hair and clean the skin thoroughly."
Al-Harith bin Wajih is alone in narrating this hadith with a connected chain, and the hadith scholars have criticised him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 827
Sulayman bin Farrukh says: I met Abu Ayyub (may Allah be pleased with him) and shook hands with him. He found my nails long and said: A man came to the Prophet (peace and blessings be upon him) and asked about the news of the heavens (revelation). The Messenger of Allah (peace and blessings be upon him) said: "One of you asks about the news of the heavens while he leaves his nails like the talons of birds, in which janabah (impurity) and dirt collect."
(b) These are the words of al-Asfati; a large group narrates it in this way from the narrator Qurash. Abu Dawud al-Tayalisi (may Allah have mercy on him) also recorded this hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 828
Wa'il bin Sulaym says: I came to Abu Ayyub al-Azdi and shook hands with him. He saw my long nails and said: A man came to the Prophet (peace and blessings be upon him) asking him something, and he (peace and blessings be upon him) said: "One of you asks me about the news of the heavens (revelation) while he leaves his nails like the talons of birds, in which janabah (impurity) and dirt collect." This narration is mursal (its chain skips the Companion). Abu Ayyub al-Azdi is someone other than Abu Ayyub al-Ansari (may Allah be pleased with him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 829