We have already shown that Jesus can be regarded neither as an arrogant man, nor a sorcerer; and therefore it is unnecessary to repeat our former arguments, lest, in replying to the tautologies of Celsus, we ourselves should be guilty of needless repetition. And now, in finding fault with our Lord's genealogy, there are certain points which occasion some difficulty even to Christians, and which, owing to the discrepancy between the genealogies, are advanced by some as arguments against their correctness, but which Celsus has not even mentioned.
For Celsus, who is truly a braggart, and who professes to be acquainted with all matters relating to Christianity, does not know how to raise doubts in a skilful manner against the credibility of Scripture. But he asserts that the “framers of the genealogies, from a feeling of pride, made Jesus to be descended from the first man, and from the kings of the Jews.” And he thinks that he makes a notable charge when he adds, that “the carpenters wife could not have been ignorant of the fact, had she been of such illustrious descent.”
But what has this to do with the question? Granted that she was not ignorant of her descent, how does that affect the result? Suppose that she were ignorant, how could her ignorance prove that she was not descended from the first man, or could not derive her origin from the Jewish kings? Does Celsus imagine that the poor must always be descended from ancestors who are poor, or that kings are always born of kings? But it appears folly to waste time upon such an argument as this, seeing it is well known that, even in our own days, some who are poorer than Mary are descended from ancestors of wealth and distinction, and that rulers of nations and kings have sprung from persons of no reputation.
Source: Against Celsus (New Advent)