Observe now with regard to the following statement of Celsus, “We see also those persons who in the market-places perform most disreputable tricks, and collect crowds around them,” whether a manifest falsehood has not been uttered, and things compared which have no resemblance. He says that these individuals, to whom he compares us, who “perform the most disreputable tricks in the market-places and collect crowds, would never approach an assembly of wise men, nor dare to show off their tricks before them; but wherever they see young men, and a mob of slaves, and a gathering of foolish people, there do they thrust themselves in and make a display.”
Now, in speaking thus he does nothing else than simply load us with abuse, like the women upon the public streets, whose object is to slander one another; for we do everything in our power to secure that our meetings should be composed of wise men, and those things among us which are especially excellent and divine we then venture to bring forward publicly in our discussions when we have an abundance of intelligent hearers, while we conceal and pass by in silence the truths of deeper import when we see that our audience is composed of simpler minds, which need such instruction as is figuratively termed “milk.”
Source: Against Celsus (New Advent)