***For you folks, not for us. ;) ***
God promised Abraham...
"...And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice."
Historically, it is Jesus of Nazareth alone who has turned people from every nation to seek the blessings of the God of Abrahan, Isaac & Jacob.
Today, 2.1 billion people, one third of the population of the world align themselves with the historic faith of Abraham and the Jewish (and Christian) Scriptures as the Word of God - all because of Jesus Christ.
Whether you believe him to be Messiah or not, it certainly appears that he is fulfilling God's ancient promise to Abraham.
There's a very interesting passage in the bible (read old testament), that says that G-d shall send different prophets to different people.
Regardless, since those 2.1 billion people are charged with following G-d's laws, and being decent people, I have no complaints.
You have to remember, though, that Jews don't seek to convert others (for the most part). We welcome converts, but we aren't supposed to proselytize. Non-Jews do not need to follow the halakha laws to secure a place in the world to come, for example; only Jews do.
Thus, I love Christians as my brothers and sisters, because they worship the same G-d as I do, and follow the commandments as I do. And I applaud Jesus and his disciples for making the world a better place. But I can't accept Jesus as the Messiah without betraying my own faith and ignoring the scriptural conditions for the arrival of the messiah. ;)
Doesn't mean I won't stand up for Christianity and Christians when push comes to shove, though. Or defend the name and deeds of Christianity from those who would try to sully its name (because if I am not for my brother, who is for me?).
Same G-d, but to put it glibly, I'll wait to embrace the Messiah: and if it's his second time here, I'll say I'm sorry for doubting, and hope I'm forgiven.
And if he says he can't remember...Well, then, we'll call it a draw! (But everyone wins because the Messiah is here) ;)