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.
Hadith Referenceسنن ابي داود / كتاب الطهارة / 249
Hadith Gradingالألبانی:ضعيف | زبیر علی زئی:إسناده حسن, مشكوة المصابيح (444)
Hadith Takhrij« سنن ابن ماجہ/الطھارة 106 (599) مسند احمد (1/101، سنن الدارمی/الطھارة 69(778)، (تحفة الأشراف: 10090) (ضعیف) » (عطاء بن سائب اخیر عمر میں اختلاط کا شکار ہو گئے تھے، اور حماد بن سلمہ نے ان سے دونوں حالتوں میں روایت کی ہے، اب پتہ نہیں یہ روایت اختلاط سے پہلے کی ہے یا بعد کی ؟)
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