There are complexities to Contra Celsum. The first is that Origen admits that a few chapters into it that he didn't like the original work and rewrote it. Is this Origen speaking or Eusebius? Because Eusebius seems to have also taken an interest in refuting Celsus as part of his war against pagan critics of Christianity (cf. Porphyry).
Indeed as it stands now Contra Celsum is NOT a handling of Celsus's True Word in the order the arguments appeared in that treatise. This is apparent when certain statements from Celsus's treatise appear twice in Contra Celsum.
The fact that Celsus's Jew appears first in Contra Celsum doesn't make sense from the point of view of Celsus's treatise. But Origen - or Eusebius - doesn't name the anti-Christian writer (Philo?) and takes special care to handle his arguments in the first two books of Contra Celsum.
BUT IF we take the order as it stands it would seem that the following words at the end of Book 3 form the context for the statements Giuseppe cites:
After having brought against us charges of so serious a kind, he wishes to make it appear that, although he has others to adduce, he passes them by in silence. His words are as follows: "These charges I have to bring against them, and others of a similar nature, not to enumerate them one by one, and I affirm that they are in error, and that they act insolently towards God, in order to lead on wicked men by empty hopes, and to persuade them to despise better things, saying that if they refrain from them it will be better for them." In answer to which, it might be said that from the power which shows itself in those who are converted to Christianity, it is not at all the "wicked" who are won over to the Gospel, as the more simple class of persons, and, as many would term them, the "unpolished." For such individuals, through fear of the punishments that are threatened, which arouses and exhorts them to refrain from those actions which are followed by punishments, strive to yield themselves up to the Christian religion, being influenced by the power of the word to such a degree, that through fear of what are called in the word "everlasting punishments," they despise all the tortures which are devised against them among men,--even death itself, with countless other evils,--which no wise man would say is the act of persons of wicked mind. How can temperance and sober-mindedness, or benevolence and liberality, be practised by a man of wicked mind? Nay, even the fear of God cannot be felt by such an one, with respect to which, because it is useful to the many, the Gospel encourages those who are not yet able to choose that which ought to be chosen for its own sake, to select it as the greatest blessing, and one above all promise; for this principle cannot be implanted in him who prefers to live in wickedness.
But if in these matters any one were to imagine that it is superstition rather than wickedness which appears in the multitude of those who believe the word, and should charge our doctrine with making men superstitious, we shall answer him by saying that, as a certain legislators replied to the question of one who asked him whether he had enacted for his citizens the best laws, that he had not given them absolutely the best, but the best which they were capable of receiving; so it might be said by the Father of the Christian doctrine, I have given the best laws and instruction for the improvement of morals of which the many were capable, not threatening sinners with imaginary labours and chastisements, but with such as are real, and necessary to be applied for the correction of those who offer resistance, although they do not at all understand the object of him who inflicts the punishment, nor the effect of the labours. For the doctrine of punishment is both attended with utility, and is agreeable to truth, and is stated in obscure terms with advantage. Moreover, as for the most part it is not the wicked whom the ambassadors of Christianity gain over, neither do we insult God. For we speak regarding Him both what is true, and what appears to be clear to the multitude, but not so clear to them as it is to those few who investigate the truths of the Gospel in a philosophical manner.
Seeing, however, that Celsus alleges that "Christians are won over by us through vain hopes," we thus' reply to him when he finds fault with our doctrine of the blessed life, and of communion with God: "As for you, good sir, they also are won over by vain hopes who have accepted the doctrine of Pythagoras and Plato regarding the soul, that it is its nature to ascend to the vaults of heaven, and in the super-celestial space to behold the sights which are seen by the blessed spectators above. According to you, O Celsus, they also who have accepted the doctrine of the duration of the soul (after death), and who lead a life through which they become heroes, and make their abodes with the gods, are won over by vain hopes. Probably also they who are persuaded that the soul comes (into the body) from without, and that it will be withdrawn from the power of death, would be said by Celsus to be won over by empty hopes. Let him then come forth to the contest, no longer concealing the sect to which he belongs, but confessing himself to be an Epicurean, and let him meet the arguments, which are not lightly advanced among Greeks and Barbarians, regarding the immortality of the soul, or its duration (after death), or the immortality of the thinking principle;, and let him prove that these are words which deceive with empty hopes those who give their aSsent to them; but that the adherents of his philosophical system are pure from empty hopes, and that they indeed lead to hopes of good, or--what is more in keeping with his opinions--give birth to no hope at all, on account of the immediate and complete destruction of the soul (after death). Unless, perhaps, Celsus and the Epicureans will deny that it is a vain hope which they entertain regarding their end,--pleasure,--which, according to them, is the supreme good, and which consists in the permanent health of the body, and the hope regarding it which is entertained by Epicurus.
And do not suppose that it is not in keeping with the Christian religion for me to have accepted, against Celsus, the opinions of those philosophers who have treated of the immortality or after-duration of the soul; for, holding certain views in common with them, we shall more conveniently establish our position, that the future life of blessedness shall be for those only who have accepted the religion which is according to Jesus, and that devotion towards the Creator of all things which is pure and sincere, and un-mingled with any created thing whatever. And let him who likes show what "better things" we persuade men to despise, and let him compare the blessed end with God in Christ,--that is, the word, and the wisdom, and all virtue;-which, according to our view, shall be bestowed, by the gift of God, on those who have lived a pure and blameless life, and who have felt a single and undivided love for the God of all things, with that end which is to follow according to the teaching of each philosophic sect, whether it be Greek or Barbarian, or according to the professions of religious mysteries; and let him prove that the end which is predicted by any of the others is superior to that which we promise, and consequently that that is true, and ours not befitting the gift of God, nor those who have lived a good life; or let him prove that these words were not spoken by the divine Spirit, who filled the souls of the holy prophets. And let him who likes show that those words which are acknowledged among all men to be human, are superior to those which are proved to be divine, and uttered by inspiration. And what are the "better" things from which we teach those who receive them that it would be better to abstain? For if it be not arrogant so to speak, it is self-evident that nothing can be denied which is better than to entrust oneself to the God of all, and yield oneself up to the doctrine which raises us above all created things, and brings us, through the animate and living word--which is also living wisdom and the Son of God--to God who is over all. However, as the third book of our answers to the treatise of Celsus has extended to a sufficient length, we shall here bring our present remarks to a close, and in what is to follow shall meet what Celsus has subsequently written.