Surat Al A`raf: (184-185)

{أَوَلَمْ يَتَفَكَّرُواْ مَا بِصَاحِبِهِم مِّن جِنَّةٍ إِنْ هُوَ إِلاَّ نَذِيرٌ مُّبِينٌ} [الأعراف: 184]

184- Did not the disbelievers of Quraysh who disbelieved in Muhammad (peace be upon him) think that Muhammad was not touched by madness or sorcery as they claimed?! He was the true Messenger of Allah; that was clear to every mindful person.

{أَوَلَمْ يَنظُرُواْ فِي مَلَكُوتِ السَّمَاوَاتِ وَالأَرْضِ وَمَا خَلَقَ اللّهُ مِن شَيْءٍ وَأَنْ عَسَى أَن يَكُونَ قَدِ اقْتَرَبَ أَجَلُهُمْ فَبِأَيِّ حَدِيثٍ بَعْدَهُ يُؤْمِنُونَ} [الأعراف: 185]

185- Do not those disbelievers ponder over the creation of heavens and the earth to prove the power, greatness, and the oneness of Allah?! They should direct their acts of worship to Allah alone and leave out the worship of idols because their lifetimes may be short and they die before they believe then their final destination shall be hell? So, in what warning and admonition after the Qur'an which Muhammad (peace be upon him) brought them they would believe after he had explained to them the means of faith and saved them from Hell-Fire?