The author says: One of the causes of occultation is fear as mentioned in tradition. Imam Musa Kazim عليه السلام also used to keep his Imamate confidential from others. In the same way his Shias who had faith in his Imamate but feared the people, also did not discuss openly about his Imamate. So much so that when Hisham bin Hakam was asked in the court of Yahya bin Khalid who the Imam of that time was, Hisham resorted to dissimulation and said: The owner of the palace, chief of believers, Harun Rashid.
At that Harun Rashid was listening to this dialogue secretly. He said: By God, Allah has put a cruel ruler over us. When Hisham came to know that Harun has summoned him, he fled to Kufa and passed away there. In compliance of his will, his bier was placed at the Kanasa highway and a slip of paper was placed in his hand on which was written: This is Hisham bin Hakam who was summoned by the ruler of the time. The chief Qadi and government officials saw this. After that, the rebellious one gave up pursuing him.
Commentary #1
At that Harun Rashid was listening to this dialogue secretly. He said: By God, Allah has put a cruel ruler over us. When Hisham came to know that Harun has summoned him, he fled to Kufa and passed away there. In compliance of his will, his bier was placed at the Kanasa highway and a slip of paper was placed in his hand on which was written: This is Hisham bin Hakam who was summoned by the ruler of the time. The chief Qadi and government officials saw this. After that, the rebellious one gave up pursuing him.