Excerpt from 'Nafasul Mahmum':
The retainer lifted his sword and started walking with the children. They had not reached far from the house, when one child told him, 'O black slave! You resemble Bilal the Mu’ezzin (the caller of Prayer) of the Prophet of Allah (S).'The retainer said, 'My master has ordered me to kill you, but tell me as to who you are?'
They replied, 'We are from the progeny of your Prophet Muhammad (S), and have escaped from the prison of Ubaydullah bin Ziyad in fear of death. The woman had offered us shelter in her house while your master intends killing us.'The retainer fell on their feet and kissing them said, 'May my life be your ransom, and may my face act as a shield for yourselves, O children of Allah’s chosen Prophet! By Allah! I shall not perform the act which would invite the wrath of Muhammad (S) on the day of Qiyamah.'
Saying this he threw away his sword and jumped into the sea and swam away to the opposite shore. When his master saw it he screamed, 'You have disobeyed me.' To which he replied, 'I have never disobeyed you until you yourself disobeyed Allah. And now that you have disobeyed Allah, I disown you in this world as well as the Hereafter.'
Then the man called his son and said, 'I have gathered for you through lawful and unlawful means, while this world is such that it should be acquired. Hence take these children to the shore of Euphrates and severe their heads and bring them to me, so that I may take them to Ubaydullah and get two thousand dirhams as reward for it.' His son lifted the sword and started walking ahead of them.
They had not reached far when one of the child told him, 'O youth! How I fear your youth being burnt in the fire of hell.' The youth asked them as to who they were? They replied, 'We are from the progeny of your Prophet, and your father intends killing us.'
Hearing this, the youth fell upon their feet and kissing them repeated the words of the slave and jumped into the sea and swam to the opposite shore. When his father saw this he called out, 'You disobey me?' To which he replied, 'Allah’s obedience is more dear (to me) than your’s.' Hearing this the accursed said, 'No one will be ready to kill you except myself', saying this he lifted the sword and went towards them.
When they reached the shore of Euphrates, he unsheathed his sword. When the infants saw the naked sword, their eyes became full of tears. Then they said, 'O Shaikh! Take us to the market and sell us and do not invite the wrath of the Prophet in Qiyamah.' He replied, 'No, verily I shall kill you and take your heads to Ubaydullah and thereby earn reward from him.'
They said, 'O Shaikh! Do you not consider the relation we share with the Prophet?' To which he said, 'Verily you have no relation with the Prophet as such.' They again said, 'O Shaikh! Then take us to the presence of Ubaydullah, so that he may decide what to do with us.'
He replied, 'I do not have any other way, except that I may earn his nearness by spilling your blood.'
The children said, 'O Shaikh! Do you not have pity upon our infancy?' to which he replied that, 'Allah has not allotted mercy in my heart.' Then they said, 'O Shaikh! Now that there is no hope left, give us respite to recite some units of Prayers.' He said, 'Pray as much as you like if it benefits you.' The children recited four units of Prayers, then lifted their eyes towards the heavens and cried, 'O Ever-Living! O Wise! O the Best of Judges! Judge between us with righteousness.'
He stood up and severed the head of the elder brother and kept his head in a bag. The younger brother, who had smeared his body in the blood of his elder brother, said, 'I desire to meet the Prophet of Allah (S) in this very state drenched in the blood of my brother.' He said, 'Do not fear, for I shall soon join you with your brother', saying this he severed his head too and placed it in the bag. Then he threw their bodies into the river of Euphrates.