The Prophet ﷺ was asked about a person who had his head shaved before slaughtering (his Hadi) (or other similar ceremonies of Hajj). He replied, "There is no harm, there is no harm."  

سُئِلَ النَّبِيُّ ﷺ عَمَّنْ حَلَقَ قَبْلَ أَنْ يَذْبَحَ وَنَحْوِهِ فَقَالَ لاَ حَرَجَ لاَ حَرَجَ  

A man said to the Prophet ﷺ "I performed the Tawaf-al-Ifada before the Rami (throwing pebbles at the Jamra)." The Prophet ﷺ replied, "There is no harm." The man said, "I had my head shaved before slaughtering." The Prophet ﷺ replied, "There is no harm." He said, "I have slaughtered the Hadi before the Rami." The Prophet ﷺ replied, "There is no harm."  

رَجُلٌ لِلنَّبِيِّ ﷺ زُرْتُ قَبْلَ أَنْ أَرْمِيَ قَالَ لاَ حَرَجَ قَالَ حَلَقْتُ قَبْلَ أَنْ أَذْبَحَ قَالَ لاَ حَرَجَ قَالَ ذَبَحْتُ قَبْلَ أَنْ أَرْمِيَ قَالَ لاَ حَرَجَ وَقَالَ عَبْدُ الرَّحِيمِ الرَّازِيُّ عَنِ ابْنِ خُثَيْمٍ أَخْبَرَنِي عَطَاءٌ عَنِ ابْنِ عَبَّاسٍ ؓ عَنِ النَّبِيِّ ﷺ وَقَالَ الْقَاسِمُ بْنُ يَحْيَى حَدَّثَنِي ابْنُ خُثَيْمٍ عَنْ عَطَاءٍ عَنِ ابْنِ عَبَّاسٍ ؓ عَنِ النَّبِيِّ ﷺ وَقَالَ عَفَّانُ أُرَاهُ عَنْ وُهَيْبٍ حَدَّثَنَا ابْنُ خُثَيْمٍ عَنْ سَعِيدِ بْنِ جُبَيْرٍ عَنِ ابْنِ عَبَّاسٍ ؓ عَنِ النَّبِيِّ ﷺ وَقَالَ حَمَّادٌ عَنْ قَيْسِ بْنِ سَعْدٍ وَعَبَّادِ بْنِ مَنْصُورٍ عَنْ عَطَاءٍ عَنْ جَابِرٍ ؓ عَنِ النَّبِيِّ ﷺ  

The Prophet ﷺ was asked by a man who said, "I have done the Rami in the evening." The Prophet ﷺ replied, "There is no harm in it." Another man asked, "I had my head shaved before the slaughtering." The Prophet ﷺ replied, "There is no harm in it."  

سُئِلَ النَّبِيُّ ﷺ فَقَالَ رَمَيْتُ بَعْدَ مَا أَمْسَيْتُ فَقَالَ لاَ حَرَجَ قَالَ حَلَقْتُ قَبْلَ أَنْ أَنْحَرَ قَالَ لاَ حَرَجَ  

I came upon Messenger of Allah ﷺ when he was at Al-Batha. He asked me, "Have you intended to perform the Hajj?" I replied in the affirmative. He asked, "For what have you assumed lhram?" I replied," I have assumed Ihram with the same intention as that of the Prophet ﷺ ." The Prophet ﷺ said, "You have done well! Go and perform Tawaf round the Kaʿba and between Safa and Marwa." Then I went to one of the women of Bani Qais and she took out lice from my head. Later, I assumed the Ihram for Hajj. So, I used to give this verdict to the people till the caliphate of ʿUmar. When I told him about it, he said, "If we take (follow) the Holy Book, then it orders us to complete Hajj and ʿUmra (Hajj-at- Tamattuʿ) and if we follow the tradition of Messenger of Allah ﷺ then Messenger of Allah ﷺ did not finish his lhram till the Hadi had reached its destination (had been slaughtered). (i.e. Hajj-al-Qiran). (See Hadith No. 630)  

قَدِمْتُ عَلَى رَسُولِ اللَّهِ ﷺ وَهُوَ بِالْبَطْحَاءِ فَقَالَ أَحَجَجْتَ قُلْتُ نَعَمْ قَالَ بِمَا أَهْلَلْتَ قُلْتُ لَبَّيْكَ بِإِهْلاَلٍ كَإِهْلاَلِ النَّبِيِّ ﷺ قَالَ أَحْسَنْتَ انْطَلِقْ فَطُفْ بِالْبَيْتِ وَبِالصَّفَا وَالْمَرْوَةِ ثُمَّ أَتَيْتُ امْرَأَةً مِنْ نِسَاءِ بَنِي قَيْسٍ فَفَلَتْ رَأْسِي ثُمَّ أَهْلَلْتُ بِالْحَجِّ فَكُنْتُ أُفْتِي بِهِ النَّاسَ حَتَّى خِلاَفَةِ عُمَرَ ؓ فَذَكَرْتُهُ لَهُ فَقَالَ إِنْ نَأْخُذْ بِكِتَابِ اللَّهِ فَإِنَّهُ يَأْمُرُنَا بِالتَّمَامِ وَإِنْ نَأْخُذْ بِسُنَّةِ رَسُولِ اللَّهِ ﷺ فَإِنَّ رَسُولَ اللَّهِ ﷺ لَمْ يَحِلَّ حَتَّى بَلَغَ الْهَدْىُ مَحِلَّهُ