Shia traditional reports on the topic that Imams are twelve in number

H 106 - It is narrated from Abil Husain that he said: Narrated to me a group of scholars from Abu Muhammad Talakbari from Abil Husain Muhammad bin Ja’far Asadi from Sahal bin Ziyad Adami from Hasan bin Abbas bin Harish Razi from Imam Jawad عليه السلام that Amirul Momineen عليه السلام said to Ibn Abbas: “Surely, the night of power (Lailatul Qadr) occurs every year. In this night, the affairs of that year descend. For this affair, there are masters after the Messenger of Allah صلى الله عليه وعلى آله وسلم.” Ibn Abbas inquired, ‘Who are they?’ He عليه السلام replied, “I and eleven Imams from my progeny, with whom the angels converse (Muhhaddithun).”