Prophet Muhammad (s.a.) said: “The difficulties I had to face were unlike anything faced by the earlier prophets (a.s.).”
Regarding this tradition, Ayatullah Shaykh Iraqi writes that, here the Prophet (s.a.) apart from his other afflictions, wishes to tell us about a tribulation in particular that was unique in nature, in the sense that none of the previous prophet were subjected to it. And that tribulation was the hostile treatment meted out to the Ahl ul Bayt (a.s.) after the demise of Prophet (s.a.). Among the hardships that the Ahl ul Bayt (a.s.) were made to face, was Karbala.
Allah had informed the Prophet (s.a.) about the incident of Karbala through Jibrail. The Prophet (s.a.) was always very grievous and sorrowful about the incidents that were to follow him. So Allah (as to console him) taught the prophet (s.a.) Ziyarat Ashura and enumerated its benefits in the world and the hereafter. And Allah took it up on Himself to grant all the requests and ease all hardships through its recitation. Allah gave this Ziyarat to Jibrail and asked him to present it to the Prophet (s.a.), so as to gladden the Ahl ul Bayt (a.s.) and their Shias, the reciters of this Ziyarat would be contented and pleased with its benefits in the hereafter and gain relief from the adversities of this world.
That is why Imam Sadiq (a.s.), and he narrated from his great grandfather Imam Husayn (a.s.), and he from his brother Imam Hasan Mujtaba (a.s.), and he from his father Ali b. Abi Talib (a.s.), and he from the Prophet (s.a.), and he from Jibrail, and he from Qalam, and Qalam from Lauh, and Lauh from Allah, the Almighty Allah has guaranteed that, if one is in distress and seeks fulfillment of his demands with the recitation of this Ziyarat, then Allah with His might and majesty, and for the love of Ahl ul Bayt (a.s.) will satisfy his demands.
Imam Jafar Sadiq (a.s.) recounts: “O Safwaan! When you are confronted with some adversity, then seek redressal of your grievances from Imam Husayn (a.s.) through the Amal of Ashura. Allah has pledged the fulfillment of demands with this Ziyarat and Allah never reneges on His word.” Hardships and afflictions no matter how severe can be remedied by reciting Ziyarat Ashura for forty consecutive days.
Miracles of Ziyarat e Ashura – P.E.T Publications