Why do we begin to commemorate the martyrdom of Hussein (PBUH) from the first day of Muharram and end on the…

Answer

In the name of Allah, we follow our Imams (PBUH) in doing this. They were adhering to the grief of the first of Muharram, in addition to the fact that the calamity on the master of the martyrs started from the first Muharram. He came down in Karbala on the second day of Muharram and before he came down he was besieged by the army of Obeid Allah ibn Ziad and skirmishes between enemies and among the companions of Hussein began before the tenth day. Allah is the all-Guide and Helper.