'Abu al-Hasan Musa b. Ja'far, for about ten years, performed a single prostration from sunrise until noon. [He continued], 'Harlin would sometimes climb onto a roof that overlooked the prison cell wherein he had imprisoned Abu al-Hasan. He would see Abu al-Hasan (AS) in prostration. He asked al-Rab!', 'What is that cloth I see on that spot everyday?' He said, ?O commander of the faithful! That is not a cloth but Musa b. Ja'far (AS). He performs a prostration every day from sunrise until noon.' Harlin said, 'He is indeed one of the holy men from the Bani Hashim.' I asked, 'Then why have you confined him to captivity?' He said, 'Alas! That is how it must be.'