I am with you (egw meta umwn). This is the amazing and blessed promise. He is to be with the disciples when he is gone, with all the disciples, with all knowledge, with all power, with them all the days (all sorts of days, weakness, sorrows, joy, power), till the consummation of the age (ew th sunteleia tou aiwno). That goal is in the future and unknown to the disciples. This blessed hope is not designed as a sedative to an inactive mind and complacent conscience, but an incentive to the fullest endeavor to press on to the farthest limits of the world that all the nations may know Christ and the power of his Risen Life. So Matthew's Gospel closes in a blaze of glory. Christ is conqueror in prospect and in fact. Christian history from that eventful experience on the Mountain in Galilee has been the fulfilment of that promise in as far as we allow God's power to work in us for the winning of the world to Christ, the Risen, all powerful Redeemer, who is with his people all the time. Jesus employs the prophetic present here (eimi, I am). He is with us all the days till he comes in glory.