Plain as day it says to kill them unless they have joined a group you have a treaty with or approach with breast restrained.There is no specifically stated penalty for irtidad in the Qur'an. Even Maududi (RA) acknowledges that only those who "instigated apostasy" were deserving of death according to his interpretation of At-Tawbah.Why not use the Quran to illustrate the penalty for apostasy in Islam?There is one Islam and you know nothing of it.
Narrated Jabir bin 'Abdullah: A Bedouin gave the Pledge of allegiance to Allah's Apostle for Islam and the Bedouin got a fever, whereupon he said to the Prophet, "Cancel my Pledge." But the Prophet refused. He came to him (again) saying, "Cancel my Pledge." But the Prophet refused. Then (the Bedouin) left (Madinah). Allah's Apostle said: "Madinah is like a pair of bellows: it expels its impurities and brightens and clears its good." - Sahih Bukhari, Ahkam, no. 89
It is a capital offense if the act of irtidad involves fasad.
The hadith above shows that execution cannot be the hadd punishment for irtidad; Rasul Allah (SAWS) would have applied it himself in that case.
4:89. They wish that you reject Faith, as they have rejected (Faith), and thus that you all become equal (like one another). So take not Auliyâ' (protectors or friends) from them, till they emigrate in the Way of Allâh (to Muhammad SAW). But if they turn back (from Islâm), take (hold) of them and kill them wherever you find them, and take neither Auliyâ' (protectors or friends) nor helpers from them.
4:90. Except those who join a group, between you and whom there is a treaty (of peace), or those who approach you with their breasts restraining from fighting you as well as fighting their own people. Had Allâh willed, indeed He would have given them power over you, and they would have fought you. So if they withdraw from you, and fight not against you, and offer you peace, then Allâh has opened no way for you against them.
The Noble Quran : Surat 4
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