Why do Jews reject Christianity?
One of my teachers expounded the following thought: When you consider the development of all religions in the world, Judaism stands out as unique. All of the other religions begin with a supposed communication between G-d and an individual (e.g. Jesus/Paul, Mohammed, etc). Only Judaism makes the claim that G-d spoke to an entire nation of some three million people. If it had not happened as recorded, then it is highly improbable that an entire nation could be duped into believing, “a national revelation occurred, but every single one of your ancestors forget to tell you….â€?
Christianity expects people to base their faith on the veracity of a communication between G-d and a single person. This was a communication that, if it did occur, no one else heard, and is, therefore, inherently unverifiable. Ergo, believing in a religion on that basis is logically unjustifiable, and is rejected by the Jews.