" In Matthew, Jesus declares, “Whoever is not with me is against me.” In Mark, he says,“Whoever is not against us is for us.” Did he say both things? Could he
mean both things? How can both be true at once? Or is it possible that
one of the Gospel writers got things switched around? "

― Bart D. Ehrman , Jesus, Interrupted: Revealing the Hidden Contradictions in the Bible & Why We Don't Know About Them