Luke says that the Spirit came down on the disciples at Pentecost, after the Lord’s ascension, with power to open the gates of life to all nations and to make known to them the new covenant. So it was that men of every language joined in singing one song of praise to God, and scattered tribes, restored to unity by the Spirit, were offered to the Father as the first fruits of all the nations.
This was why the Lord had promised to send the Advocate: he was to prepare us as an offering to God. Like dry flour, which cannot become one lump of dough, one loaf of bread, without moisture, we who are many could not become one in Christ Jesus without the water that comes down from heaven. And like parched ground, which yields no harvest unless it receives moisture, we who were once like a waterless tree could never have lived and borne fruit without this abundant rainfall from above. Through the baptism that liberates us from change and decay we have become one in body; through the Spirit we have become one in soul. … We need the dew of God.