The earth, as a whole, was created, in the eyes of the Imam to be a worshipping place, a concept first presented by the Apostle of Allah (s.a.w.).  This life was created so that people could serve and glorify Allah, the Most High.  It is merely a trip towards Allah, and an attempt to know Him better.  The Imam wouldn't feel a change in time or place.  All the times and places for him were the same.  One the contrary, the more he was persecuted, the closer he got to Allah (swt) by means of patience and prayer.  He made his prison a mosque, and his loneliness and the dreariness of the jail a pleasant place filled with the remembrance of Allah, the Most High.  He fasted during the day, and prayed and recited supplication in the night, staying up until daybreak.One of those charged with keeping a watchful eye on the Imam in the prison of Isa bin Ja'far related that he had heard the Imam praying, "O Allah, You know that i had been asking You to free me from any obligation except worshipping You.  Now You have done that.  So, praise be to You."   

        On account of that, Isa bin Ja'far wrote to al-Rasheed, after he had kept the Imam in his jail, saying, "Take him, and put him in the care of anyone you like.  Otherwise I will set him free.  I tried hard to find a way to incriminate him, but found none.  I went to the point of eaves-dropping, that he might invoke evil upon me or you, but I heard him only asking Allah's mercy and forgiveness for himself."   

        Ahmad bin Abdullah is reported to have said, quoting his father, "I called on al-Fadhl bin al-Rabi.  He was sitting on the roof of his house.  'Look at this house,' said he, 'What do you see?'  'A discarded garment,' replied I.  'Look well,' he urged.  I examined the thing narrowly and said, 'A prostrate man.'  'Do you know him?' he said.  'He is Musa bin Ja'far.  I keep close watch on him, during the day and in the night.  Never did I see him anytime in another position.  He says his dawn prayer and recites the post-prayer supplications, until sunrise.  Then he kneels down in prostration, and remains so until midday.  He asked someone to tell him prayer times.  When the man tells him about the time of a certain prayer, he jumps performing the prayer without renewing his ablution.  That is his habit, saying   his sunset prayer, he breaks his fasting.  He keeps performing prayer in the dead night until day breaks."   

        Imam Musa Al-Kadhim (a.s.) influences his jailers.  He passed his time in prison reciting supplication, asking Allah's forgiveness.  He devoted him time to worship, regarding the trial of imprisonment as a favor and mercy conferred on him by Allah (swt).   

        What kind of man is this?  What force could overcome him?  The light of his heart swept away the darkness of the prison.  The firmness of his patience shattered the shackles of the jailer and the will of the tyrant.  The pleasantness of his prayers filled up the gloomy prison with happiness and brightness.  What could the jailer ever do?  What could the tyrant do?  Imam Musa Al-Kadhim (a.s.) was winning over those who were around him with his good manners, deep spirituality and unique wisdom.   

        Al-Amiri, in his book "Al-Anwar", reports that "Haroon al-Rasheed sent a maid to Imam Musa bin Ja'far (a.s.) to serve him in prison.  She was beautiful, with a bright face and black eyes.  Imam Musa bin Ja'far (a.s.) commented on this saying, 'Nay, you are excellent because of your gift'.  'I have no need of this or to the likes of her.'  Hearing that, Haroon got furious.  'Go back to him,' he ordered his servant, 'and tell him that it was not with your consent that we have jailed you.  Nor was it with your consent that we have captured you. Leave the maid there and come back.'   

         The servant did what he had been ordered to do.  Haroon then left the room where he used to receive guests and visitors and sent the servant back to see the maid and what had become of her.  He saw her prostrate saying, "O Holy One.  Glory to You.  Glory to You." 'By Allah', Haroon commented, 'Musa bin Ja'far has bewitched her with witchcraft..."   

        Maybe Haroon desired to lure Imam Musa Kadhim (a.s.) away from his sacred objectives with the beauty of women, and the pleasures of life, acting out his own flawed convictions.  He didn't know that Imam al-Kadhim (a.s.) was totally absorbed in the beauty of right, and dissolved in the love of Allah.  He had turned his face away from life and its cheap ornaments.  Neither maids could occupy his attention, nor life's pleasures would fascinate him.  He was a man with a mission, who dedicated his whole life to his principles, and submitted his whole soul to Allah, the Glorified.  As a result, he became a man guiding with his words and actions, and a preacher who showed the right path with both his silence and speech.  His action spoke instead of his tongue, and his words declared the path of right.  That is why he overcame the maiden's mind and soul.  She cried, "O Holy One. O Glorified One," captured in her prostration.  After basking in the pleasures of entertainment, drinking from the cups of love, passing her time playing musical instruments, singing love poems, and enjoying wearing fine clothes and necklaces, she turned to worship.  She went on with her prayers and praises of Allah until she passed away.  It is said that her death occurred a few days before the martyrdom of Imam Musa Al-Kadhim (a.s.).   

        Imam al-Kadhim (a.s.) braved all difficulties and hardships on the thorny path of faith.  He taught the men who came after him, who treaded the same path, how to be firm in their attitudes, and steadfast inside prisons, not frightened by their jailers, or the oppression they practiced against them so as to silence them.  Imam al-Kadhim (a.s.), on the orders of al-Rasheed, was transferred from one prison to another.  He was first sent to Isa bin Ja'far, then to al-Fadhl bin al-Rabi, then to al-Fadhl bin Yahya, and finally to al-Sindi bin Shahik.  Al-Rasheed meant to hide Imam Musa (a.s.), drive him out from the attention of the ummah and kill it's spirit of resistance.  The result was quite the opposite.  The ummah was eager to follow the latest news about Imam Musa al-Kadhim (a.s.), especially when he was moved from one prison to another, with the authorities unable to take a decisive action against him.  Being in prison was of great value for Imam Musa al-Kadhim (a.s.).  He nurtured the revolution, rejection and resistance, conferring legitimacy on them.  That is why he turned down all offers to intervene on his behalf with the rulers.  He frankly told those who asked him to allow them to send a delegation of prominent people to al-Rasheed to persuade him to set him free, "My father told me on the authority of his father and grandfather that Allah, the Mighty and Glorified, gave Dawood (David) this piece of advice:  'Dawood, whoever from My servants clings to one of My creatures, turning his face from Me, insisting on that, shall certainly be deprived from heaven's support by Me.  I shall make the earth sink under his feet."   

        When al-Rasheed felt that the silent resistance of Imam Musa (a.s.) in prison began to sneak into people's souls, and that his uncompromising attitude moved the ummah's awareness and feelings, fear took hold of him, for that awareness might grow into a violent revolution.  He consulted his vizier, Yahya bin Khalid, who advised him to release Imam Musa al-Kadhim (a.s.).   

        Allamah al-Majlisi, in his book "Bihar al-Anwar", says that, When al-Rasheed threw Abu-Ibrahim Musa in prison, and saw some miracles made by him, he was greatly perplexed.  He sent for Yahya bin Khalid al-Barmaki. 'Abu-Ali' he said, 'Do you not see what wonders we are witnessing?  Can you manage this man and spare us his troubles?'  'What I see as the best solution, Commander of the Faithful,' said Yahya bin bin Khalid, 'is that you do him a favor by being kind to him as he is your relative.  He has, by Allah, spoiled the hearts of your followers.'  Yahya was a follower of Imam Musa (a.s.) without the knowledge of Haroon. 'Go instantly to him,' ordered Haroon, 'relieve him of his shackles, remember me to him, and say to him, 'Your cousin says to you that Yahya has interceded with me on your behalf, and that I will not release you until you have admitted your wrong doings and asked forgiveness for what you have done against me.  No shame will be attached to your admittance; nor will it be a flaw on your part to ask my pardon..."   

        When Yahya conveyed the message of al-Rasheed to Imam Musa bin Ja'far (a.s.), he rejected the offer which would have put him in a humiliating position, as if he were a wrongdoer.  He said to Yahya, Tomorrow, when we have knelt down before Allah, Who would judge between us, you would know who was the oppressor who had wronged the other.  Wassalam."   

        In this way, Imam Musa al-Kadhim (a.s.) defeated  all means of injustice and terror, like prison, pressure, chains, distortion of the truth, and deceiving public opinion.  Al-Rasheed was left with only one choice, to assassinate Imam Musa al-Kadhim (a.s.), and put an end to his blessed life.   

        He thought he could, by committing such a horrible crime, bring down the curtain on one of the greatest scenes of jihad and resistance against tyranny, extinguish the light of Imamate of Ahlul Bayt (a.s.), and get rid of the greatest intellectual and  religious figures of his time.   
        For such considerations, he made up his mind to assassinate him.   
   
The Martyred Imam:   
    By all means, Al-Rasheed tried to get rid of Imam Musa bin Jafar (a.s.).  The Imam, being a man of great social, religious and intellectual position, was a nightmare for al-Rasheed.  Hearts of people hovered over Imam al-Kadhim (a.s.).  They loved Ahlul Bayt (a.s.).  No Muslim could ever say that he knew nothing about them.  People respected them.  Nobody dared ignore their glorious position and their status in the eyes of the Messenger of Allah (s.a.w.), except those who greedily sought spoils of life and trampled all ideals and values under their feet.  Even these worthless people could not make public their enmity toward Ahlul Bayt (a.s.); nor could they fight them without twisting the facts to suit their purposes.  That is why Isa bin Ja'far, the governor of Basrah, refused to kill him, asking al-Rasheed to relieve him of this task and transfer Imam Musa (a.s.) to another prison.  Being in prison of al-Fadhl bin al-Rabi, Imam Musa (a.s.) impressed him.  Al-Fadhl bin Yahya who treated him kindly and made his prison a bit comfortable.  When al-Rasheed asked him to slay Imam Musa (a.s.) he declined.  When word came that al-Fadhl bin Yahya treated his prisoner well, al-Rasheed was enraged.  He ordered him to be punished.  Al-Fadhl was stripped naked and given 100 lashes in the assembly hall of al-Abbas bin Muhammad.   

        Casting around him, al-Rasheed found no one better than the chief of his police in Baghdad, al-Sindi bin Shahik, a man known to be rough, stone-hearted and merciless, like other criminals, to murder the Imam.   

        As we have seen, al-Sindi bin Shahik received Imam Musa (a.s.) from al-Fadhl bin Yahya, and put him in his prison.  He burdened him with heavy chains and fetters, treating him most brutally and inhumanly.  Yahya bin Khalid, one the other hand, was agonized by the punishment of his son, al-Fadhl, had receive from al-Rasheed.  He decided to propitiate al-Rasheed and restore his family's position before the Abbasid ruler.  The price would be the blood of Imam Musa al-Kadhim (a.s.) even if that would torture the Holy Prophet (s.a.w.).   

        Base people do such things.  Controlled by meanness, opportunism and sycophancy, they seek the closeness of the rulers and blood-thirsty tyrants by shedding blood and persecuting innocent people who preached righteousness.  They are dazzled by the fake social reputation and passing pleasures.  They act out of the inferiority complex which overpowers them and prods them to win other's favor.   

        Yahya ibn Khalid talked the matter over with al-Rasheed.  He assured him that al-Fadhl was an inexperienced young man.  He offered to go to Baghdad.  Al-Rasheed was not delighted at having an offer from an obedient, faithful man.  He gave him the green light to perpetrate the crime.  Arriving in Baghdad, Yahya instantly held a meeting with al-Sindi bin Shahik, during which he explained to him the plan he had set to get rid of the Imam (a.s.).  the latter accepted it gratefully.  According to the plan, poison was given to Imam Musa al-Kadhim (a.s.) in a plate of dates, or in some other food, according to another version.  Imam Musa (a.s.) partook from that food and felt the poison sneaking through his pure body.  For three days, he struggled with death, before breathing his last.  One the third day, he died at the prison of al-Sindi bin Shahik, or at the mosque of Haroon, which was called Al-Musayyab Mosque.  He won martyrdom on the 25th of Rajab, in the year 183 A.H.   

        Imam Musa al-Kadhim's (a.s.) start set, and his light faded away from the sky of a bereaved Baghdad.  Dark descended on the city, whose sky was cloudy with sorrow and anguish.  Her blank eyes were swelled with the tears of separation and bereavement.  She flung aside the false flag of  peace her founder had concurred on her, and put on the clothes of mourning and protest.  She cried out, "I am no longer the city of peace, nor a resting place for the free, righteous men."  The hangman sat perplexed.  Before him the crime was flashing.  The horror of such a heinous act filled him with remorse.  This terrorist, al-Sindi bin Shahik, felt the graveness of the tragedy.  He saw Baghdad seething with anger and tumult.  All the criminals who were involved in the conspiracy saw it.  The voice of right was loud on every tongue filling all parts of Baghdad, "The Imam died without doing any wrong.  He was martyred in the tyrant's prison."   

Reference  
Al-Balagh Foundation.  Imam al-Kadhim.  Ahlul-Bait, book 9. Pages 90-99.  Tehran, Islamic Republic of Iran.