In his response to John's disciples, Jesus was claiming that the fulfillment of the OT hope with its attendant blessings was in fact present in his person and ministry. The fulfillment, however, was not taking place along expected lines, hence John’s perplexity. The unexpected element was that fulfillment was taking place in Jesus, but without the eschatological consummation. The OT prophetic hope of the coming Messianic kingdom of God as promised to Israel is being fulfilled in the person and ministry of Jesus, but not consummated. The Jews of our Lord’s day, in keeping with what they saw in the OT, expected the consummation of the kingdom, the complete and final overthrow of Israel’s political enemies and the ushering in of the age of blessed peace and prosperity in the land. Our Lord, however, came with the message that before the kingdom would come in its eschatological consummation it has come in his own person and work in spirit and power. The kingdom, therefore, is both the present spiritual reign of God and the future realm over which He will rule in power and glory. (Taken from Sam Storms 2 part articles on the not yet & already of the kingdom... they look to be very good)