Liars would have left it out
Further, Celsus’s Jew says to Jesus’ disciples, as though they had made these things up: “Not even by lying were you able to cover up your fictions convincingly.” To this it will be said that there was an easy way to cover up such things: not to record them at all in the first place. For if the Gospels did not contain these things, who could have reproached us because Jesus spoke such words in the course of the divine plan?
Celsus did not see that the same people cannot both have been deceived about Jesus, as though he were God and the one foretold in prophecy, and also have invented things about him, plainly knowing that their inventions were not true. Either, then, they did not invent them but believed these things and wrote without lying, or they lied in what they wrote, did not believe these things, and were not deceived into thinking him God.
Greek
Ἔτι δὲ λέγει ὁ παρὰ τῷ Κέλσῳ Ἰουδαῖος πρὸς τοὺς Ἰησοῦ μαθητὰς ὡς πλασαμένους ταῦτα. ὅτι οὐδὲ ψευδόμενοι τὰ πλάσματα ὑμῶν πιθανῶς ἐπικαλύψαι ἠδυνήθητε. καὶ πρὸς τόδε λελέξεται ὅτι εὐχερὴς μὲν ἦν ὁδὸς πρὸς τὸ ἐπικαλύψαι τὰ τοιαῦτα τὸ μηδὲ τὴν ἀρχὴν αὐτὰ ἀναγράψαι. τίς γὰρ ἂν τῶν εὐαγγελίων ταῦτα μὴ περιεχόντων ὀνειδίσαι ἐδύνατο ἡμῖν ἐπὶ τῷ τὸν Ἰησοῦν τοιαῦτα παρὰ τῇ οἰκονομίᾳ λελαληκέναι; οὐ συνεῖδε δ᾿ ὁ Κέλσος ὅτι οὐκ ἔστι κατὰ τοὺς αὐτοὺς καὶ ἠπατῆσθαι περὶ τοῦ Ἰησοῦ ὡς θεοῦ καὶ προφητευθέντος καὶ πλάσασθαι περὶ αὐτοῦ δηλονότι ἐγνωκότας ὅτι οὐκ ἀληθῆ τὰ πλάσματα. ἤτοι οὖν οὐκ ἔπλασαν ἀλλ᾿ οὕτως ἐφρόνουν καὶ οὐ ψευδόμενοι ἀνέγραψαν. ἢ ψευσάμενοι ἀνέγραψαν καὶ ταῦτα οὐκ ἐφρόνουν οὐδὲ ἀπατηθέντες θεὸν αὐτὸν ἐνόμιζον.