actually , Kuffieh wasn't a Shia city back then , most of Kuffis who sent letters to Imam Housein just wanted political benefit for themselves and didn't truly seen him as their Imam ... some of them were just angry about Damscus being capital , some others hated Ummawis ...a sect which kills the family of their own founder cant be a true follower.
and you don't know whole story , most of shiia leaders were arrested before the chaos and was limited in Kuffa ...( and some of there were naive enough to think that Ibn Ziad army won't do anything to prophet descends and Bani Hashem and in worst case they will just force Imam Housein to goes back to Medina ------- after Karrballah they become Tav'vaabin )
and in fact before Karballa event there wasn't a real and tangible different between Islamic sects , it was more political matter rather that religious matter ( although it was wrong ) ...
and shiia with these clear idea about Imamat founded through time and with activity of Imam Sajjad ( 4th Imam ) , Imam Baqer ( 5th Imam ) , Imam Jaffar Sadeq ( 6th Imam ) and Imam Mousa Kazem ( 7th Imam ) and Imam Reza ( 8th Imam ) and so ...
our Imam could prove their righteousness with Quran and Hadith after Karrballa ...
Last edited: