PUT YOURSELF IN THEIR PLACE. Think of the early disciples, supposedly forced into silence because of the danger to all followers of Jesus, but in fact galvanized into unity of action by the overwhelming proof they'd just seen in the crucifixion, resurrection, and ascension of their Teacher. Proof that all the hatred and violence in the world hurled at a single individual still could not extinguish love, could not snuff out life. Not when that life and love were understood spiritually, as the disciples had been taught to understand them. Jesus' message was real, transforming, stupendously powerful. And the proof of it was repeatable, at least in some degree. By them. By all followers, for all time to come.
During those days following the resurrection and ascension, Christ Jesus' teaching and example must have come into sharper focus than ever before, and the disciples' own purpose must have come into clearer outline. It's a time that continues to be instructive to church members of the 21st century yearning for a more unified course of action.
Fifty days after the resurrection came the day of Pentecost. Some historians pinpoint it as the moment when the Christian Church was born. The disciples were "all with one accord in one place," filled with the Holy Spirit, and preaching the gospel of Christ so that "every man heard them speak in his own language." See Acts 2:1—6. Despite the unprecedented nature of all this, in retrospect it seems inevitable. Given what those disciples had gone through together, how could they not be so in accord with one another, so filled with the same Spirit?