Excerpt from 'The Life of Fatimah Az-Zahra', The Principle of All Women: Study and Analysis':
Umar and some other companions attacked Fatimah and Ali’s (peace be upon them) house and threatened of setting fire to it. The following are the narrations of the historians who have mentioned this fact:
Al-Balathiri
Al-Balathiri mentioned that Abu Bakr sent for Imam Ali to pay homage to him but Imam Ali (a.s.) refused to pay homage. Therefore Umar came with a wick. Fatimah (s.a.) met him at the door and said to him, 'Shall you set fire to my door?'He said, 'Yes, and this is stronger than what your father had brought.'
At-Tabari
He mentioned: 'Umar came to Ali’s house wherein there were Talha, az-Zubayr and some men from the Muhajireen, and said to them, ‘By Allah, I will burn (the house) over you or you come out to the homage.’ Az-Zubayr went out drawing his sword, but he stumbled and fell to the ground and the sword fell from his hand. They (Umar and his fellows) jumped on and took him.'
Ibn Abd Rabbih
He said: 'Those who did not pay homage to Abu Bakr were Ali, al-Abbas, az-Zubayr and Sa’d bin Ubada. As for Ali, al-Abbas and az-Zabayr, they remained in Fatimah’s house until Abu Bakr sent to them Umar bin al-Khattab to make them get out of Fatimah’s house. He said to him, ‘If they refuse, you should fight them.’ Umar came with a torch intending to set fire to the house. Fatimah (s.a.) met him and said, ‘O ibn al-Khattab, have you come to burn our house?’ He said, ‘Yes, or you enter into what the nation has entered into.'
Ibn Abil Hadeed
He said, 'Umar came to Fatimah’s house with some men from the Ansar and a few from the Muhajireen and said, ‘I swear by Whom in Whose hand Umar’s soul is, either you come out for the homage or I will burn the house over you.'
Ash-Shahristani
Ash-Shahristani mentioned from an-Nidham that Umar was shouting: 'Set fire to her (Fatimah) house with all those in it.' There were none but Ali, Fatimah, al-Hasan and al-Husayn inside the house.
Kahhala
Umar Redha Kahhala said, 'Abu Bakr found that some men had defaulted his homage like al-Abbas, az-Zubayr and Sa’d bin Ubada. They were with Ali bin Abi Talib in Fatimah’s house. Abu Bakr sent to them Umar bin al-Khattab who called out to them while they were inside Fatimah’s house. They refused to come out. Umar ordered firewood to be brought. He said, ‘I swear by Whom in Whose hand Umar’s soul is, either you come out (for the homage) or I will set fire to it (the house) over all those in it.’
It was said to him, ‘O Abu Hafs, Fatimah is there.’
He said, ‘Even though!’'
Al-Mas’oodi
He mentioned that al-Abbas went to Ameerul Mo'minin (Imam Ali) when the messenger of Allah (S) died. Ameerul Mo'minin and some men of his followers remained in his house with what the messenger of Allah had entrusted him. People (Abu Bakr’s men) attacked his house, set fire to the door and took him out by force. They pressed the Principal of Women behind the door.
The fact of their determination to set fire to Imam Ali and Fatimah’s (peace be upon them) house is certain and has no way for doubt.
Sheikh al-Majlisi quoted from Irshad al-Qulub that Fatimah (s.a.) said,
'Umar took the whip from Qunfudh’s hand and stroke with it my upper arm and the whip wound on my arm and it was like a ring. Then he kicked the door with his foot against me and I was pregnant. I fell on my face to the ground. He hit me with his hand and my earring scattered. And then, I miscarried Muhsin that was killed with no guilt.'
These were some of the sources that have mentioned the event of the aggression against Fatimah (s.a.). All the Shia believe in this fact as true, and there are many traditions transmitted from the Infallible Imams (a.s.) about this event. However, these events show that those people were ready to commit anything for the sake of rule and authority.