الكافي 1/4/72/16

16. Muhammad ibn al-Hassan has narrated from Sahl ibn Ziyad from Muhammad ibn Ali and ‘Abdallah ibn al-Marzuban from (Muhammad) ibn Sinan who has said the following. “Once I went to see abu al-Hassan Musa عليه السلام one year before he would leave for Iraq. His son Ali عليه السلام was also in the meeting. He looked at me and said, “O Muhammad, during this year a movement will take place do not be disturbed in it.” The narrator has said that he then asked the Imam عليه السلام , “‘May Allah take my soul in service for your cause, what that will be? What you said has made me very anxious.” The Imam عليه السلام said, “I will journey to the tyrant. From his and one after him I will not suffer any serious harm.” The narrator has said that he then asked The Imam عليه السلام , “‘May Allah take my soul in service for your cause, what then will happen?” The Imam عليه السلام said, “ Allah causes the unjust to go astray and He does whatever He wills.” The narrator has said that he then asked the Imam عليه السلام , “‘May Allah take my soul in service for your cause, what is that will happen?” The Imam عليه السلام said, “Whoever will do injustice to my son this one, reject his Imamat (Leadership with Divine Authority) after me it would like doing injustice to Ali ibn abu Talib عليه السلام and reject his Imamat (Leadership with Divine Authority) after the Messenger of Allah.” The narrator has said that he then asked The Imam عليه السلام , “By Allah, if Allah will grant me long life I will acknowledge his right and will affirm his Imamat (Leadership with Divine Authority).” The Imam عليه السلام said, “You have spoken the truth, O Muhammad. Allah will grant you long life.You will acknowledge his right and affirm his Imamat (Leadership with Divine Authority) and the Imamat of the one after him.” The narrator has said that he then asked The Imam عليه السلام , “Who will he be?” The Imam عليه السلام said, “Muhammad, his son.” The narrator has said that he then asked The Imam عليه السلام , “From me it is agreed and accepted.”