In this section, we read of the respective and cooperative roles of the Holy Spirit and the Church:
To accomplish this, Christ sent from the Father His Holy Spirit, who was to carry on inwardly His saving work and prompt the Church to spread out. Doubtless, the Holy Spirit was already at work in the world before Christ was glorified. Yet on the day of Pentecost, He came down upon the disciples to remain with them forever (cf. John 14:16). The Church was publicly displayed to the multitude, the Gospel began to spread among the nations by means of preaching, and there was presaged that union of all peoples in the catholicity of the faith by means of the Church of the New Covenant, a Church which speaks all tongues, understands and accepts all tongues in her love, and so supersedes the divisiveness of Babel. For it was from Pentecost that the “Acts of the Apostles” took again, just as Christ was – conceived when the Holy Spirit came upon the Virgin Mary, and just as Christ was impelled to the work of His ministry by the same Holy Spirit descending upon Him while He prayed.
Pentecost is sometimes described as the “birthday of the Church,” but like many other Catholics, that terminology strikes me as weak and inadequate. The “public display” described here seems more like an Epiphany to me. Just as the Nativity was greeted by both Jews (shepherds) and Gentiles (the Magi), not to mention heaven itself, the Church manifests itself not as a ready-formed entity, but as an open, all-embracing, inclusive experience of kerygma.
God’s continuing role is an active one:
Now, the Lord Jesus, before freely giving His life for the world, did so arrange the Apostles’ ministry and promise to send the Holy Spirit that both they and the Spirit might be associated in effecting the work of salvation always and everywhere. Throughout all ages, the Holy Spirit makes the entire Church “one in communion and in ministering; He equips her with various gifts of a hierarchical and charismatic nature,” a giving life, soul – like, to ecclesiastical institutions and instilling into the hearts of the faithful the same mission spirit which impelled Christ Himself. Sometimes He even visibly anticipates the Apostles’ acting, just as He unceasingly accompanies and directs it in different ways.
We also see God’s respect for free will. Sadly, the faults of human beings have damaged the expression of apostolic ministry and the overarching value of unity (not to mention love) to such an extent that the Church doesn’t always seem to be expressive of the Divine ideals. God persists in working with us, which may be an even more profound example of grace. It’s something for which we can be thankful.