Some new thing, then, has come to pass since the time that Jesus suffered—that, I mean, which has happened to the city, to the whole nation, and in the sudden and general rise of a Christian community. And that, too, is a new thing, that those who were strangers to the covenants of God, with no part in His promises, and far from the truth, have by a divine power been enabled to embrace the truth. These things were not the work of an impostor, but were the work of God, who sent His Word, Jesus Christ, to make known His purposes. The sufferings and death which Jesus endured with such fortitude and meekness, show the cruelty and injustice of those who inflicted them, but they did not destroy the announcement of the purposes of God; indeed, if we may so say, they served rather to make them known.
For Jesus Himself taught us this when He said, “Except a grain of wheat fall into the ground and die, it abides by itself alone: but if it die, it brings forth much fruit.” Jesus, then, who is this grain of wheat, died, and brought forth much fruit. And the Father is ever looking forward for the results of the death of the grain of wheat, both those which are arising now, and those which shall arise hereafter. The Father of Jesus is therefore a tender and loving Father, though “He spared not His own Son, but delivered Him up” as His lamb “for us all,” that so “the Lamb of God,” by dying for all men, might “take away the sin of the world.”
It was not by compulsion, therefore, but willingly, that He bore the reproaches of those who reviled Him. Then Celsus, returning to those who apply abusive language to images, says: “Of those whom you load with insults, you may in like manner say that they voluntarily submit to such treatment, and therefore they bear insults with patience; for it is best to deal equally with both sides. Yet these severely punish the scorner, so that he must either flee and hide himself, or be taken and perish.”
It is not, then, because Christians cast insults upon demons that they incur their revenge, but because they drive them away out of the images, and from the bodies and souls of men. And here, although Celsus perceives it not, he has on this subject spoken something like the truth; for it is true that the souls of those who condemn Christians, and betray them, and rejoice in persecuting them, are filled with wicked demons.
Source: Against Celsus (New Advent)