It is mainly during his stay in Mecca that he received many letters from Kufa assuring him their support and asking him to come over there and guide them. He answered their calls and sent Muslim ibn Aqeel, his cousin, to Kufa as his representative in an attempt to consider the exact situation and public opinion.
Husain's representative to Kufa, Muslim ibn Aqeel was welcomed by the people of Kufa, and most of them swore allegiance to him. After this initial observation, Muslim ibn Aqeel wrote to Husain Ibn Ali that the situation in Kufa was favorable. However, after the arrival of the new Governor of Kufa, Ubayd-Allah ibn Ziyad, the scenario changed. Muslim ibn Aqeel and his host, Hani ibn Urwa, were executed on Dhu al-Hijjah 9, 60AH (September 10, 680 CE) without any considerable resistance of the people. This shifted the loyalties of the people of Kufa, in favor of Yazid against Husain ibn Ali. Husain ibn Ali also realized a deep conspiracy that Yazid had appointed `Amr ibn Sa`ad ibn al As as the head of an army, ordering him to take charge of the pilgrimage caravans and to kill al Husain ibn Ali wherever he could find him during Hajj, and hence decided to leave Mecca on 08th Dhu al-Hijjah 60 AH (12 September 680 AD), just a day before Hajj and was contented with Umrah, due to his concern about potential violation of the sanctity of the Kaaba.He delivered a famous sermon in Kaaba highlighting his reasons to leave that he didn't want the sanctity of Kaaba to be violated, since his opponents had crossed any norm of decency and were willing to violate all tenets of Islam.
When Husain ibn Ali was making his mind to leave for Kufa, Abd-Allah ibn Abbas and Abdullah ibn Zubayr held a meeting with him and advised him not to move to Iraq, or, if he was determined to move, not to take women and children with him in this dangerous journey. Husain ibn Ali, however, had resolved to go ahead with his plan. He gave a speech to people the day before his departure and said:
"... The death is a certainty for mankind, just like the trace of necklace on the neck of young girls. And I am enamored of my ancestors like eagerness of Jacob to Joseph ... Everyone, who is going to devote his blood for our sake and is prepared to meet Allah, must depart with us..."