✅ Answer: Pay attention to the following hadiths:

مُحَمَّدُ بْنُ الْحَسَنِ بِإِسْنَادِهِ عَنْ أَحْمَدَ بْنِ مُحَمَّدِ بْنِ دَاوُدَ الْقُمِّیِّ فِی نَوَادِرِهِ عَنْ مُحَمَّدِ بْنِ عِیسَی عَنْ أَخِیهِ جَعْفَرِ بْنِ عِیسَی عَنْ خَالِدِ بْنِ سَدِیرٍ أَخِی حَنَانِ بْنِ سَدِیرٍ قَالَ سَأَلْتُ أَبَا عَبْدِ اللَّهِ.... وَ لَقَدْ شَقَقْنَ الْجُیُوبَ وَ لَطَمْنَ الْخُدُودَ الْفَاطِمِیَّاتُ عَلَی الْحُسَیْنِ بْنِ عَلِیٍّ وَ عَلَی مِثْلِهِ تُلْطَمُ الْخُدُودُ وَ تُشَقُّ الْجُیُوب

📚 *Al-Tahdhib*, Vol. 8, p. 325

Translation: Imam Ja'far al-Sadiq (AS) said in a narration: Certainly, the women of the family of Fatima (peace be upon her) tore their collars for Hussain ibn Ali (AS) and slapped their faces. It is for no one like Hussain (AS) that the faces are slapped and collars are torn.

مُحَمَّدُ بْنُ عَلِیِّ بْنِ الْحُسَیْنِ قَالَ لَمَّا قُبِضَ عَلِیُّ بْنُ مُحَمَّدٍ الْعَسْکَرِیُّ رُئِیَ الْحَسَنُ بْنُ عَلِیٍّ ع وَ قَدْ خَرَجَ مِنَ الدَّارِ وَ قَدْ شُقَّ قَمِیصُهُ عَنْ خَلْفٍ وَ قُدَّامٍ

📚 *Man La Yahduruhu al-Faqih*, Vol. 1, p. 174

Translation: Sheikh Saduq said: When Imam Ali al-Naqi (AS) passed away, it was seen that Imam Hasan al-Askari (AS) came out of the house while his shirt was torn both in the front and the back.

عَلِیُّ بْنُ عِیسَی فِی کِتَابِ کَشْفِ الْغُمَّةِ نَقْلًا مِنْ کِتَابِ الدَّلَائِلِ لِعَبْدِ اللَّهِ بْنِ جَعْفَرٍ الْحِمْیَرِیِّ عَنْ أَبِی هَاشِمٍ الْجَعْفَرِیِّ قَالَ خَرَجَ أَبُو مُحَمَّدٍ فِی جَنَازَةِ أَبِی الْحَسَنِ وَ قَمِیصُهُ مَشْقُوقٌ فَکَتَبَ إِلَیْهِ ابْنُ عَوْنٍ مَنْ رَأَیْتَ أَوْ بَلَغَکَ مِنَ الْأَئِمَّةِ شَقَّ قَمِیصَهُ فِی مِثْلِ هَذَا فَکَتَبَ إِلَیْهِ أَبُو مُحَمَّدٍ یَا أَحْمَقُ وَ مَا یُدْرِیکَ مَا هَذَا قَدْ شَقَّ مُوسَی عَلَی هَارُونَ

📚 *Kashf al-Ghama*, Vol. 2, p. 418

Translation: Abu Hashim al-Ja'afari said: Abu Muhammad Imam al-Askari (AS) came out over the body of Abu al-Hasan (the 10th Imam) while his shirt was torn. Abu Awn wrote to him: Have you seen any of the Imams or heard of any who tore their shirt in such a calamity?! The Imam replied to him: O fool, what do you know about this? Indeed, Prophet Musa (AS) tore his collar in the death of his brother Harun.

✅: In addition to the above hadiths, there are other evidences from narrations and historical accounts that, firstly, tearing the collar is permissible for all the Imams (AS), and secondly, this type of mourning, in the case of Imam Hussain (AS) and the other members of the Ahl al-Bayt, is a good and commendable tradition. Unfortunately, this practice is not widely observed among the lovers of Ahl al-Bayt (AS), and we should revive this tradition of slapping the face and tearing the collar during mourning for the great calamity of our master Imam Hussain (AS), in order to protect ourselves and others from some innovations in mourning rituals.