What is Narrated From Al-Askari عليه السلام Regarding the Designation of Al-qa'im

Narrated to us Ahmad bin Muhammad bin Yahya al-Attar رضي الله عنه: Narrated to us Saad bin Abdullah: Narrated to us Musa bin Ja’far bin Wahab Baghdadi that he said: I heard Aba Muhammad Hasan bin Ali عليه السلام say: “As if I can see you disputing after me with regard to my successor. Behold, someone who professes faith in all the Imams after the Messenger of Allah صلى الله عليه وعلى آله وسلم yet denies my son, is like someone who professes faith in all prophets and messengers of Allah and then rejects the prophethood of Muhammad the Messenger of Allah صلى الله عليه وعلى آله وسلم; and the denier of the Messenger of Allah صلى الله عليه وعلى آله وسلم is like one who rejects all the prophets. Because, obedience to our last one is obedience to our first one and rejecter of our last one is the rejecter of our first one. Behold, my son will have an occultation in which people will doubt except the ones whom Allah, the Mighty and Sublime saves.”