Hazrat Ibn Abi Mulaykah (may Allah have mercy on him) narrates that Hazrat Umar (may Allah be pleased with him) said: If Abu Bakr (may Allah be pleased with him) had obeyed us, we would have fallen into disbelief in a single morning. Because when people asked him to reduce the zakat, he refused to accept their request and said: If they withhold from me even a rope of a camel, I will surely fight against them.

Hazrat Tawus (may Allah have mercy on him) narrates that Hazrat Ibn Abbas (may Allah be pleased with them both) said: The Jews and Christians will not let you settle in their cities. So, whoever among them accepts Islam and then becomes an apostate, you should strike his neck.

Hazrat Amir (may Allah be pleased with him) narrates that Hazrat Anas bin Malik (may Allah be pleased with him) said: Some people from the tribe of Bakr bin Wa'il apostatized from Islam and joined the polytheists. Then they were killed in battle. When I brought the news of the conquest of Tustar to Hazrat Umar bin Khattab (may Allah be pleased with him), he asked: What happened to the people of the tribe of Bakr bin Wa'il? The narrator says that I started another topic in front of him so that I could divert him from mentioning them, but he asked again: What happened to the group of Bakr bin Wa'il? I replied, O Commander of the Faithful! They were killed. He said: If I had made a peace agreement with them, that would have been more beloved to me than the gold and silver upon which the sun rises. The narrator says: I said, O Commander of the Faithful! If you had captured those people who apostatized from Islam and joined the polytheists, what other way could there have been except to kill them? He replied: I would have presented to them that they enter through the same door from which they exited; if they did so, I would have accepted these things from them, and if they refused to do so, I would have imprisoned them in jails.

Hazrat Ammar al-Dahni (may Allah have mercy on him) narrates that Hazrat Abu al-Tufail (may Allah have mercy on him) said: I was present in the army which Hazrat Ali (may Allah be pleased with him) sent towards Banu Najiyah. When we reached them, we found those people divided into three groups. So our commander asked one group: What is your situation? They said: We were Christians and we accepted Islam and remained steadfast on Islam. The commander said: You separate yourselves. Then the commander asked the second group: What is your situation? They said: We were Christians. We did not consider any religion better than our own, so we remained steadfast on our religion. The commander said: You also separate yourselves. Then the commander asked the last group: What is your situation? They said: We were Christians, then we accepted Islam, then we turned back from Islam because we did not consider any religion better than our own, and we became Christians again. The commander said to them: Accept Islam. They refused. So the commander said to his companions: When I pass my hand over my head three times, then attack them. So the people did so, and killed their fighting men and took their children captive. Then I brought the captives to Hazrat Ali (may Allah be pleased with him). And Ma’qalah bin Hubayrah came and bought those captives for two hundred thousand. Then he brought one hundred thousand to Hazrat Ali (may Allah be pleased with him), but he (may Allah be pleased with him) refused to accept it. Ma’qalah took his dirhams back and went to the slaves and freed all of them, and joined Hazrat Mu’awiyah (may Allah be pleased with him). Then Hazrat Ali (may Allah be pleased with him) was asked: Why did you not take those children? He (may Allah be pleased with him) replied: No. Then he (may Allah be pleased with him) did not take any action against them.

Hazrat Abu Alaqa (may Allah have mercy on him) narrates that Hazrat Umar bin Khattab (may Allah be pleased with him) sent an army, and they found among the Muslims a man who had become a Christian after accepting Islam. So they killed that person. Then Hazrat Umar (may Allah be pleased with him) was informed of this. He asked: Did you invite him to Islam? They replied: No! He (may Allah be pleased with him) said: Surely, then I am absolved before Allah of his blood.

Hazrat Ibn Ubaid bin Abras, may Allah have mercy on him, narrates that Hazrat Ali, may Allah be pleased with him, bin Abi Talib said: Indeed, a man was brought who was a Christian, then he accepted Islam, then he became a Christian again. Hazrat Umar, may Allah be pleased with him, asked him about this matter, so he informed him. Then Hazrat Ali, may Allah be pleased with him, stood up towards him and kicked him on his chest. Then the people also stood up and began to beat him until they killed him.

Hazrat Makharraq (may Allah have mercy on him) narrates that Hazrat Ali (may Allah be pleased with him) sent Muhammad bin Abi Bakr as the governor over the people of Egypt. So he wrote a letter to Hazrat Ali (may Allah be pleased with him) and asked about the Zindiqs, some of whom worshipped the sun and the moon, and some of whom worshipped other things, and some claimed to be Muslims. Hazrat Ali (may Allah be pleased with him) wrote a letter to him and ordered regarding the Zindiqs that whoever claims to be a Muslim among them, kill him, and leave all the rest; let them worship whatever they wish.

Hazrat Haritha bin Mudarrib, may Allah have mercy on him, narrates that a man set out and mounted his horse, then he passed by the mosque of the Banu Hanifa tribe and performed prayer there. The imam of those people recited the words of Musaylimah the Liar! This man came to Hazrat Ibn Mas’ud, may Allah be pleased with him, and informed him of this matter. He, may Allah be pleased with him, sent a messenger and summoned those people. All of them were brought. Then he, may Allah be pleased with him, made all of them repent. All of them repented except Abdullah bin Nuwahah. He, may Allah be pleased with him, said to him: O Abdullah! If I had not heard the Messenger of Allah, peace and blessings be upon him, say:“If you were not a messenger, I would have struck your neck.”But today you are not a messenger. O Kharashah! Get up and strike his neck. So Kharashah got up and struck his neck.

Hazrat Qais (may Allah have mercy on him) says that a man came to Hazrat Abdullah bin Masood (may Allah be pleased with him) and said, "Indeed, I passed by the mosque of the people of the Banu Hanifa tribe. I heard their imam reciting in that Qur'an which Allah Almighty revealed to Hazrat Muhammad (peace and blessings be upon him). Then I heard him reciting these words: 'Al-Tahinatu Tahnan, Fal-Aajinatu Ajnan, Fal-Khabizatu Khabzan, Fath-Tharidatu Thardan, Fallaaqimatu Laqman!'"

The narrator says: Hazrat Abdullah bin Masood (may Allah be pleased with him) sent someone to them. Then those people were brought. One hundred and seventy men were upon the religion of Musaylimah, and their imam was Abdullah bin Nawahah. He (may Allah be pleased with him) ordered regarding him, and he was killed. Then he (may Allah be pleased with him) looked at the rest of the people and said, "We will not please Satan by killing them. Take all these people to Syria. Perhaps Allah Almighty will destroy them through the plague."

Hazrat Abdullah bin Amr (may Allah be pleased with him) narrates that Hazrat Amr bin Al-Aas (may Allah be pleased with him) wrote a letter to Hazrat Umar bin Khattab (may Allah be pleased with him) stating that indeed a man, after accepting faith, has chosen disbelief. So Hazrat Umar (may Allah be pleased with him) wrote back in reply: Ask him to repent; if he repents from it, then accept his repentance on his behalf, otherwise strike his neck.