Information concerning the work exists only in the extensive quotations from it in the Contra Celsum ("Against Celsus"), written some seventy years later by the Christian Origen.
In his opinion Christian theology was based on an amalgamation of false eastern philosophical ideas from India and Iran hastily tied together.
The only connection Celsus made between Greek philosophy and Christianity was when he asserted that "Jesus perverted the words of the philosopher" (i.e.
[12] Celsus wrote that Satan was either a mortal invention used by Christians to frighten others into believing their philosophies and joining them, or if he did indeed exist then he was proof that God was not all-powerful, but rather a weak lesser god and a bad one, for only a vindictive and insecure being would punish mankind for being tricked by an evil that he has been too weak to stop.
He claimed that Christians actively sought out and converted the ignorant, uneducated, and lower class, as they were the only people who would believe in such a ridiculous theology and blindly follow its doctrines.
[15] If an individual was from the upper class, and therefore well educated and naturally of good character, they would not be converted because they could not possibly believe in the absurd assumptions one had to in order to be considered "Christian".
Celsus revealed himself to be a member of the upper class when he makes his statements regarding Jesus, who to his mind obviously could not have been the son of God as he was born a peasant.
[17][18] Celsus' main argument against Christianity, and why he attacked it with such vigor, was that he considered it a divisive and destructive force that would harm both the Roman Empire and society.
One of the most integral parts of the Roman state religion was reverence and occasional sacrifices for the Emperor, an act that Christians continually refused to participate in, as in their opinion it came too close to idolatry and worship of a God that was not their own.
Celsus listed many reasons for how his Roman readers could easily deduce that Christianity was endangering their unity and the stability of the Empire.
Finally, Celsus and other Roman writers believed that "Christians are dangerous precisely because they put the advancement of their beliefs above the common good and the welfare of the state".