Muhammad then argued with supporting evidence to the truthfulness of what he had brought them:

[قُل لَّوْ شَآءَ اللَّهُ مَا تَلَوْتُهُ عَلَيْكُمْ وَلاَ أَدْرَاكُمْ بِهِ]

(Say: "If Allah had so willed, I should not have recited it to you nor would He have made it known to you...'') This indicates that he brought this only with the permission and will of Allah for him to do so. The proof of this was that he had not fabricated it himself and that they were incapable of refuting it, and that they should be fully aware of his truthfulness and honesty since he grew up among them, until Allah sent the Message to him. The Prophet was never criticized for anything or held in contempt. So he said,

[فَقَدْ لَبِثْتُ فِيكُمْ عُمُراً مِّن قَبْلِهِ أَفَلاَ تَعْقِلُونَ]

(Verily, I have stayed among you a lifetime before this. Have you then no sense) Which meant "don't you have brains with which you may distinguish the truth from falsehood'' When Heraclius, the Roman king, asked Abu Sufyan and those who were in his company about the Prophet , he said: "Have you ever accused him of telling lies before his claim'' Abu Sufyan replied: "No.'' Abu Sufyan was then the head of the disbelievers and the leader of the idolators, but he still admitted the truth. This is a clear and irrefutable testimony since it came from the enemy. Heraclius then said: "I wondered how a person who does not tell a lie about others could ever tell a lie about Allah.'' Ja`far bin Abu Talib said to An-Najashi, the king of Ethiopia: "Allah has sent to us a Messenger that we know his truthfulness, ancestral lineage, and honesty. He stayed among us before the prophethood for forty years.''

[فَمَنْ أَظْلَمُ مِمَّنِ افْتَرَى عَلَى اللَّهِ كَذِبًا أَوْ كَذَّبَ بِآيَـتِهِ إِنَّهُ لاَ يُفْلِحُ الْمُجْرِمُونَ ]

(17. So who does more wrong than he who forges a lie against Allah or denies His Ayat Surely, the criminals will never be successful!)