Why did G-D choose the Jews as his children?

And make a covenant with them promising eternal life. Is it because Jesus was Jewish? And if so why don't the Jews believe Jesus was messiah? I know Jesus didn't fulfill the prophesies that the old testament specified in order to recognize the messiah when he comes. Why do Christians believe Jesus is messiah? I mean if you saw him perform miracles, of course you'd believed him, but why is everybody else supposed to go off blind faith? Why aren't these miracles performed for each generation, so that all benefit from the first hand experiences of the people in Jesus' day?