"Whoever disbelieved in Allah after his belief, except him who is forced thereto and whose heart is at rest with Faith; but such as open their breasts to disbelief, on them is wrath from Allah, and theirs will be a great torment." "This was abrogated, and an exception was made, as Allah said: "Then, verily, your Lord for those who emigrated after they had been put to trials and thereafter strove hard and fought (for the Cause of Allah) and were patient, verily, your Lord afterward is, Oft-Forgiving, Most Merciful." This was 'Abdullah bin Sa'd bin Abi As-Sarh who was the governor of Egypt and used to write to the Messenger of Allah [SAW]. The Shaitan misled him and he went and joined the unbelievers. So he (the Prophet [SAW]) commanded that he be killed on the day of the Conquest of Makkah. Then, 'Uthman bin 'Afan sought protection for him, and the Messenger of Allah [SAW] granted him protection." (Using translation from Nasāʾī 4069)  

فِي سُورَةِ النَّحْلِ {مَنْ كَفَرَ بِاللهِ مِنْ بَعْدِ إِيمَانِهِ إِلَّا مَنْ أُكْرِهَ} [النحل 106] إِلَى {وَلَهُمْ عَذَابٌ عَظِيمٌ} [النحل 106] فَنُسِخَ وَاسْتُثْنِيَ مِنْ ذَلِكَ فَقَالَ {ثُمَّ إِنَّ رَبَّكَ لِلَّذِينَ هَاجَرُوا مِنْ بَعْدِ مَا فُتِنُوا ثُمَّ جَاهَدُوا وَصَبَرُوا إِنَّ رَبَّكَ مِنْ بَعْدِهَا لَغَفُورٌ رَحِيمٌ} [النحل 110] وَهُوَ عَبْدُ اللهِ بْنُ سَعْدِ بْنِ أَبِي سَرْحٍ الَّذِي كَانَ عَلَى مِصْرَ كَانَ يَكْتُبُ لِرَسُولِ اللهِ ﷺ فَأَزَلَّهُ الشَّيْطَانُ فَلَحِقَ بِالْكُفَّارِ فَأَمَرَ بِهِ أَنْ يُقْتَلَ يَوْمَ الْفَتْحِ وَاسْتَجَارَ لَهُ عُثْمَانُ بْنُ عَفَّانَ فَأَجَارَهُ رَسُولُ اللهِ ﷺ