Allah commanded Rasulullah SAW to give the message that Ali ibn Abi Talib SA is the wali of Allah, the warrior of Islam, and the rightful successor and wasi of Mohammed SAW. Rasulullah SAW performed nass on Ali ibn Abi Talib SA and declared him Amir ul Mumineen. He in turn performed nass on his son Imam Hasan SA. The Imamate was transferred from him to his brother, Imam HusainSA, and henceforth passed on from father to son. The seat of the Imamate is never empty.
Imam Jafar us Sadiq SA, the fifth Imam, performed nass on his son Imam Ismail SA, and informed his followers of the fact. During the time of Imam Sadiq SA, Abu-d- Dawaniq persecuted the descendants of Amir ul Mumineen SA for fear of losing public support in favor of Imam Sadiq SA. Deceptive and sly, he wrote to Imam Jafar us Sadiq SA extending warm hospitalities, and invited Imam Sadiq SA to send Imam Ismail SA to stay at his palace. Imam Jafar us Sadiq SA, aware of the deceitful nature of Abu-d-Dawaniq, rather than sending his heir Imam Ismail SA into the clutches of the tyrant, journeyed to Iraq.
Upon Imam Sadiq’s SA return to Hijaz, he secluded his son Imam Ismail SA from the public eye for nearly a year and four months. Imam Ismail SA passed away in seclusion. Before passing away, Imam Ismail SA performed nass on his son Imam Mohammed SA.
Imam Sadiq SA, at the funeral verified that it was in fact Imam Ismail SA, who had died by revealing the Imam’s face, and asked the public to testify whether or not it was his son, at which point they all attested to the fact that it was. Imam Ismail’s SA qabar mubarak is in Jannat ul Baqee, Al Medina.
History records that Imam Ismail SA, after his death appeared in the city of Basara. A follower of Aimmat Tahereen SA saw the Imam SA and recognized him. He asked the Imam to cure him by placing his hand on his back, upon which the Imam did, and the man was cured. News of the miracle spread throughout Basara, and word spread that Imam Ismail SA was still alive. When the news reached the ears of Abu-d-Dawaniq, he called Imam Jafar us Sadiq SA and demanded an explanation. Imam Sadiq SA recounted the testimonies of the people who had been present at the funeral, by which he verified that he had in fact buried his son, Imam Ismail SA.
The line of Imamate is never broken and has continued through Imam Mohammed bin Ismail SA after his father.