Wright on Matthew 28:18-20

"The final promise, that Jesus will be with his people 'until the close of the age", belongs closely within the 'two-age' stream of Pharisaic/rabbinic Judaism, and also of early Christianity, particularly Paul. The point here is that the 'age to come' has now been launched with Jesus' resurrection, and that the risen Jesus represents and embodies this new age, and hence becomes the human bridge between it and the present one. His promise to be 'with you always' is thus at the same time the fulfillment of the Emmanuel promise, and with it of YHWH's promise to be with even a small group of worshippers as though they were actually in the Temple itself. It is also the sign that in him the eschaton has come to birth, so that his people are guaranteed safe passage through the present age and into the long-awaited age to come."

-N.T. Wright, The Resurrection of the Son of God, 645.