Know this ultimate reality clearly -- Imam Hussain and Imam Hasan are Syeds of the youth of Jannah, loved by Sayyadi Rasul Allah (sm) so much that if anyone hurts or harms or hates Imam Hussain, he would considered as the enemy of Rasul Allah (sm) himself. All Sunni and Shia traditions agree to these facts. NO dispute at all. 

Also, understand the fact that Sayyadi Rasul Allah (sm) had already given the warning through Wahee that Imam Hussain would be made shaheed in Karbala. This Hadees is noted in Sunni traditions also and well known. At that time, Imam Hussain was just a baby and playing on the chest of Sayyadi Rasul Allah and upon hearing this news, Sayyadi Rasul Allah (sm) also cried a lot !!