When we turn to the New Testament, we pass from the climate of prediction to that of fulfillment. The things which God had foreshadowed by the lips of His holy prophets He has now, in part at least, brought to accomplishment . . . The supreme sign of the Eschaton is the resurrection of Jesus and the descent of the Holy Spirit on the Church. The resurrection of Jesus is not simply a sign which God has granted in favour of His son, but is the inauguration, the entrance into history, of the times of the End.--William Manson, 'Eschatology and the New Testament,' in Scottish Journal of Occasional Papers 2 (Edinburgh: Oliver & Boyd, 1953), 6
Christians, therefore, have entered through the Christ into the new age . . . What had been predicted in Holy Scripture as to happen to Israel or to man in the Eschaton has happened to and in Jesus.
When we read something in the NT like 'Behold, now is the day of salvation' (2 Cor 6:2), that's not mainly a call for heightened evangelistic intensity. It is mainly an eschatological statement. The 'day of salvation' in its Isaianic context was a reference to the coming day of the Lord. The end of the ages has come. The latter days are now. We have been in the latter days for 2,000 years! (The best resource here is Greg Beale's 'The Eschatological Conception of New Testament Theology' in this 1997 book.)