This excerpt is taken from Sheikh al-Islam Imam Ibn Taymiyyah's book Al-Jawab al-Bahir fi Zuwar al-Maqabir, translated by Sheikh Ataullah Saqib.
The Declaration of Monotheism by Siddiq Akbar
It is narrated in Sahih Bukhari that when the Prophet Muhammad ﷺ passed away, Siddiq Akbar (Abu Bakr) رضي الله عنه gave a sermon to the people and said:
من كان يعبد محمدا فإن محمدا قدمات ومن كان يعبد الله فان الله حى لا يموت
"Whoever worshipped Muhammad ﷺ should know that he has passed away. And whoever worshipped Allah should know that Allah is alive and will never die."
Then he recited this verse from the Holy Quran:
وَمَا مُحَمَّدٌ إِلَّا رَسُولٌ قَدْ خَلَتْ مِن قَبْلِهِ الرُّسُلُ ۚ أَفَإِن مَّاتَ أَوْ قُتِلَ انقَلَبْتُمْ عَلَىٰ أَعْقَابِكُمْ ۚ وَمَن يَنقَلِبْ عَلَىٰ عَقِبَيْهِ فَلَن يَضُرَّ اللَّهَ شَيْئًا ۗ وَسَيَجْزِي اللَّهُ الشَّاكِرِينَ ﴿١٤٤﴾
"Muhammad is no more than a messenger; messengers have passed away before him. If he dies or is killed, will you then turn back on your heels? And he who turns back on his heels will never harm Allah at all; but Allah will reward the grateful."
Reference: (3-Al Imran:144)
When Siddiq Akbar recited this verse, the Companions felt as if they were hearing it for the first time that day. Consequently, at that moment, this verse was on everyone's tongue.
Reference: (Sahih Bukhari, Kitab al-Maghazi: Bab Marad al-Nabi ﷺ wa Wafaatuhu, Hadith: 4354)
Reduction in the Impact of the Quran for the Pious and the Polytheists
At the time of a sudden incident, the meaning of some verses of the Quran becomes obscure even to the most intelligent minds. But when they are reminded, they understand. The Quran explains this as follows:
إِنَّ الَّذِينَ اتَّقَوْا إِذَا مَسَّهُمْ طَائِفٌ مِّنَ الشَّيْطَانِ تَذَكَّرُوا فَإِذَا هُم مُّبْصِرُونَ ﴿٢٠١﴾ وَإِخْوَانُهُمْ يَمُدُّونَهُمْ فِي الْغَيِّ ثُمَّ لَا يُقْصِرُونَ ﴿٢٠٢﴾
"Indeed, those who are pious, if an evil thought from Satan touches them, they immediately become alert and then it becomes clear to them what the correct course of action is. As for their brothers, they are led astray by their misguidance, and they leave no effort unturned in misleading them."
Reference: (7-Al-A'raf:201-202)