In Isaiah we read of the Servant songs, a collection of poems or songs speaking of the servant of God. There are ancient Rabbinic sources that see Isaiah 53 as referring explicitly to a suffering Messiah. The Babylonian Talmud, the midrash on Ruth, the Aramaic Targum, the writings of Moses Maimonides, and the mystical texts of the Zohar all contain exegesis to this effect.
We have two strains of thought in these servant songs - the suffering Messiah and the reigning Messiah. Christians have interpreted these texts as referring to the First and Second Comings of Christ. At the critical turning point of the Gospel, Jesus asks his disciples "Who do people say I am?" It is here that Peter gives his confession and Jesus the prediction of his crucifiction. He then goes on to talk about discipleship and his Second Coming. In Mathew 16:27 we read a prediction about the Son of Man at the End of Time.
Christ came 2000 years ago to show us the way, but he showed more. He, of his own will, voluntarily died for our sins and was raised again triumphantly. This triumphance was not seen by everyone and he did not remain on Earth to reign. There is a great deal yet to be established. Our Earth is not yet the Messianic Kingdom; there is more yet to be accomplished in this great drama. A great drama that includes each of us.