If he were inspired by others every day and night...
If he were inspired by others every day and night, how would it be possible to remain hidden from others? Moreover the verses of Qur'an were revealed to him in journey, among people, in solitude and in all conditions. Additionally, the holy Qur'an was a collection of doctrinal teachings, religious ordinances, laws and some part of the story of the prophets. When all of the holy Qur'an was sent down, it was not like what was in Old and New Testaments as well as Arab superstitious legends.
If we compare both of them, we see what the truth is, because those scriptures were full of superstitions while these verses were free from any superstition.
Therefore, answering these groundless accusations, the last concerned verse says: "Say: 'He sent it down Who knows the secrets in the heavens and the earth...." It refers to this matter that the content of this Book and its various mysteries that are about sciences, the history of former nations, laws, man's needs, even some secrets of nature and news about the future, all indicate that it is not the product of man's mind and it is not compiled by the help of such and such persons.
It is in fact generated by One Who knows mysteries of heavens and the earth and nothing is out of His knowledge realm. Nevertheless, the path of return is open to those who are liar and evil thinkers, and, in the end of the verse, it says: "... Verily He is ever Forgiving, Merciful'." In agreement with His Mercy, He has sent prophets and heavenly Books, and in agreement with His forgiveness, He pardons our countless sins in the light of faith and penance.
Why has not an angel been sent down to him, to be a warner with him?" " Or why has not a treasure been bestowed on him, or why has he not a garden to eat of it?' And the unjust say: 'You follow none other than a man bewitched'." Occasion of Revelation: Imam Hassan 'Askara (a.s.) said that he asked his father, the tenth Imam, whether the Prophet (p.b.u.h.) argued against seeking pretext and reproaches of the Jews and pagans.