The Quran root ر أ س r-’-s

وَأَتِمُّوا الْحَجَّ وَالْعُمْرَةَ لِلَّهِ فَإِنْ أُحْصِرْتُمْ فَمَا اسْتَيْسَرَ مِنَ الْهَدْيِ وَلَا تَحْلِقُوا رُءُوسَكُمْ حَتَّىٰ يَبْلُغَ الْهَدْيُ مَحِلَّهُ فَمَن كَانَ مِنكُم مَّرِيضًا أَوْ بِهِ أَذًى مِّن رَّأْسِهِ فَفِدْيَةٌ مِّن صِيَامٍ أَوْ صَدَقَةٍ أَوْ نُسُكٍ فَإِذَا أَمِنتُمْ فَمَن تَمَتَّعَ بِالْعُمْرَةِ إِلَى الْحَجِّ فَمَا اسْتَيْسَرَ مِنَ الْهَدْيِ فَمَن لَّمْ يَجِدْ فَصِيَامُ ثَلَاثَةِ أَيَّامٍ فِي الْحَجِّ وَسَبْعَةٍ إِذَا رَجَعْتُمْ تِلْكَ عَشَرَةٌ كَامِلَةٌ ذَٰلِكَ لِمَن لَّمْ يَكُنْ أَهْلُهُ حَاضِرِي الْمَسْجِدِ الْحَرَامِ وَاتَّقُوا اللَّهَ وَاعْلَمُوا أَنَّ اللَّهَ شَدِيدُ الْعِقَابِ ١٩٦

رُءُوسَكُمْ ruūsakum · your heads

And complete the ḥajj and ʿumrah for Allāh. But if you are prevented, then [offer] what can be obtained with ease of sacrificial animals. And do not shave your heads until the sacrificial animal has reached its place of slaughter. And whoever among you is ill or has an ailment of the head [making shaving necessary must offer] a ransom of fasting [three days] or charity or sacrifice. And when you are secure, then whoever performs ʿumrah [during the ḥajj months] followed by ḥajj [offers] what can be obtained with ease of sacrificial animals. And whoever cannot find [or afford such an animal] - then a fast of three days during ḥajj and of seven when you have returned [home]. Those are ten complete [days]. This is for those whose family is not in the area of al-Masjid al-Ḥarām. And fear Allāh and know that Allāh is severe in penalty. (Surah Al-Baqarah, 2:196)

فَإِن لَّمْ تَفْعَلُوا فَأْذَنُوا بِحَرْبٍ مِّنَ اللَّهِ وَرَسُولِهِ وَإِن تُبْتُمْ فَلَكُمْ رُءُوسُ أَمْوَالِكُمْ لَا تَظْلِمُونَ وَلَا تُظْلَمُونَ ٢٧٩

رُءُوسُ ruūsu · (is)

And if you do not, then be informed of a war [against you] from Allāh and His Messenger. But if you repent, you may have your principal - [thus] you do no wrong, nor are you wronged. (Surah Al-Baqarah, 2:279)