In like manner, as the statement is false “that the Hebrews, being (originally) Egyptians, dated the commencement (of their political existence) from the time of their rebellion,” so also is this, “that in the days of Jesus others who were Jews rebelled against the Jewish state, and became His followers;” for neither Celsus nor they who think with him are able to point out any act on the part of Christians which savours of rebellion. And yet, if a revolt had led to the formation of the Christian commonwealth, so that it derived its existence in this way from that of the Jews, who were permitted to take up arms in defence of the members of their families, and to slay their enemies, the Christian Lawgiver would not have altogether forbidden the putting of men to death; and yet He nowhere teaches that it is right for His own disciples to offer violence to any one, however wicked.
For He did not deem it in keeping with such laws as His, which were derived from a divine source, to allow the killing of any individual whatever. Nor would the Christians, had they owed their origin to a rebellion, have adopted laws of so exceedingly mild a character as not to allow them, when it was their fate to be slain as sheep, on any occasion to resist their persecutors. And truly, if we look a little deeper into things, we may say regarding the exodus from Egypt, that it is a miracle if a whole nation at once adopted the language called Hebrew, as if it had been a gift from heaven, when one of their own prophets said, “As they went forth from Egypt, they heard a language which they did not understand.”
Source: Against Celsus (New Advent)