From: Shadab Aryan
why shia muslim doing matam?
It has many answers but in short answer from shia book is what Bibi Zainab Radi Allaho Anha prayed for after Imam Hussain RadiAllaho Anho was martyred and those who did it started to do Matam .
English: Bibi zainab said o those who do Matam (Cry, beat them self in sorrow) you will keep doing this till the judgement day this is your punishment.
Urdu: BiBi Zainab K Dil Se Shia K Liye NikLi Hoi Dua e Zarar:
“Ay Matam Karne Walo Tum Qiyamat Tak Matam Hi Karte Raho Gay Yehi Tumhari Saza Hai”