Sayyiduna Ali (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings be upon him) said: "Whoever, during the ritual bath of major impurity, leaves even a single hair on his body unwashed, such and such will be done to him in Hell." Sayyiduna Ali (may Allah be pleased with him) says: That is why I became an enemy of the hair of the head. And he used to cut his hair.
Hadith Referenceمعجم صغير للطبراني / كتاب الطهارة / 141
Hadith Gradingمحدثین:ضعيف
Hadith Takhrij«ضعيف ، أخرجه أبو داود فى «سننه» برقم: 249، والدارمي فى «مسنده» برقم: 778، وابن ماجه فى «سننه» برقم: 599، قال الشيخ الألباني: ضعيف ، والبيهقي فى«سننه الكبير» برقم: 842، 1093، وأحمد فى «مسنده» برقم: 738، 805، وعبد الله بن أحمد بن حنبل فى زوائده على "مسند أحمد"، 1136، والطيالسي فى «مسنده» برقم: 170، والبزار فى «مسنده» برقم: 814، والطبراني فى «الأوسط» برقم: 7034، والطبراني فى «الصغير» برقم: 987 ، وابن أبى شيبة فى «مصنفه» برقم: 1073 قال الشيخ الألباني : ضعيف»
Narrated Ali ibn Abu Talib: The Messenger of Allah ﷺ said: If anyone who is sexual defiled leaves a spot equal to the breadth of a hair without washing, such and such an amount of Hell-fire will have to be suffered for it. Ali said: On that account I treated my head (hair) as an enemy, meaning I cut my hair. He used to cut the hair (of his head). May Allah be pleased with him.
Shaykh Umar Farooq Saeedi
Benefits and Issues: ➊ From the collection of the aforementioned narrations, it is clear that in the ritual bath (ghusl) of major impurity (janabah), a person should carefully and diligently ensure that water reaches every part of the entire body; even a hair’s breadth left dry is a cause of punishment. However, women are given a legal concession in Shari‘ah that they do not have to undo their braids, as will be mentioned ahead.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 249
´It was narrated from 'Ali bin Abu Talib that:` The Prophet said: "Whoever leaves an area the size of a hair on his body and does not cleanse it from sexual impurity, such and such will be done to him in the Fire." 'Ali said: "Because of that I am hostile towards my hair," and he used to shave his head.
Maulana Ataullah Sajid
Commentary: Keeping the hair of the head is indeed preferable, provided that it is not in the English (Western) style, but rather parted hair. However, shaving the hair off is also permissible.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 599