Some Zanadiqa (atheists) were brought to `Ali and he burnt them. The news of this event, reached Ibn `Abbas who said, "If I had been in his place, I would not have burnt them, as Allah's Messenger (ﷺ) forbade it, saying, 'Do not punish anybody with Allah's punishment (fire).' I would have killed them according to the statement of Allah's Messenger (ﷺ), 'Whoever changed his Islamic religion, then kill him.'"

Abu Musa said, "I came to the Prophet (ﷺ) along with two men (from the tribe) of Ash`ariyin, one on my right and the other on my left, while Allah's Messenger (ﷺ) was brushing his teeth (with a Siwak), and both men asked him for some employment. The Prophet (ﷺ) said, 'O Abu Musa (O `Abdullah bin Qais!).' I said, 'By Him Who sent you with the Truth, these two men did not tell me what was in their hearts and I did not feel (realize) that they were seeking employment.' As if I were looking now at his Siwak being drawn to a corner under his lips, and he said, 'We never (or, we do not) appoint for our affairs anyone who seeks to be employed. But O Abu Musa! (or `Abdullah bin Qais!) Go to Yemen.'" The Prophet then sent Mu`adh bin Jabal after him and when Mu`adh reached him, he spread out a cushion for him and requested him to get down (and sit on the cushion). Behold: There was a fettered man beside Abu Muisa. Mu`adh asked, "Who is this (man)?" Abu Muisa said, "He was a Jew and became a Muslim and then reverted back to Judaism." Then Abu Muisa requested Mu`adh to sit down but Mu`adh said, "I will not sit down till he has been killed. This is the judgment of Allah and His Apostle (for such cases) and repeated it thrice. Then Abu Musa ordered that the man be killed, and he was killed. Abu Musa added, "Then we discussed the night prayers and one of us said, 'I pray and sleep, and I hope that Allah will reward me for my sleep as well as for my prayers.'"

When the Prophet (ﷺ) died and Abu Bakr became his successor and some of the Arabs reverted to disbelief, `Umar said, "O Abu Bakr! How can you fight these people although Allah's Messenger (ﷺ) said, 'I have been ordered to fight the people till they say: 'None has the right to be worshipped but Allah, 'and whoever said, 'None has the right to be worshipped but Allah', Allah will save his property and his life from me, unless (he does something for which he receives legal punishment) justly, and his account will be with Allah?' "Abu Bakr said, "By Allah! I will fight whoever differentiates between prayers and Zakat as Zakat is the right to be taken from property (according to Allah's Orders). By Allah! If they refused to pay me even a kid they used to pay to Allah's Messenger (ﷺ), I would fight with them for withholding it." `Umar said, "By Allah: It was nothing, but I noticed that Allah opened Abu Bakr's chest towards the decision to fight, therefore I realized that his decision was right."