John 14:12

12. Greater works than these shall he do The miracles of Jesus were indeed greater displays of power than any wonder-worker, whether prophet, priest, or saint, ever wrought. Yet they were but the preparatory apparatus of Christianity. They were provisional and temporary. From them was to proceed the greater work, through the power of the Spirit and the agency of men, of establishing and fully completing the wide-spread conversion of souls, and the conquering of the world to Christ. His miracles and his words, divinely limited to a narrow territory, converted but few. They were but the bud to the flower and the fruit. Hence greater works are performed by the Church after his ascension than were performed by himself in the day of his humiliation.

Because I go unto my Father But these greater works of the future Church, after all, spring from the power of the ascended and exalted Son. It is because he goes to the Father and leaves the Spirit and the Church to labour, that the great work is performed under his divine Headship, of taking a world of free agents, and, without destroying their freedom, winning their free obedience to his Father and God.