Today’s readings for Pentecost Sunday cover the Holy Spirit being released to the world and St. Paul’s preaching that Christ’s baptized followers are members of His body (the Church), because all are in the one Spirit.
We can extrapolate that as the soul is the form and life of the body, the Holy Spirit is the form and life of the body of Christ, the Church. Hence, the Church is an organism born on Pentecost, with Christ as its Head and the Holy Spirit its Soul.
We can see why Pentecost is referred to as the “birthday of the Church.” After 9 days – each day representing a month – the Spirit prompted the apostles to leave the womb of the Upper Room to be manifest to the world. This enabled the Spirit through them to covert 3000 people that day. The Spirit has been animating and guiding the body of Christ ever since, as it grows and matures through the centuries.
We can also surmise that if Pentecost is the birth of the Church, its conception occurred before then when Jesus breathed the Holy Spirit onto His apostles, enabling them to forgive sins and celebrate the Eucharist in His name. As an embryo Church, the apostles went into the upper room to attach themselves to God in prayer – as every embryo moves into the womb to attach himself to the mother’s uterine wall. After nine days (metaphorically 9 months), the fetal Church left the Upper Room and was born into the world.
So, like any organism, the Church was conceived (in the apostles), born (on Pentecost), and matures, with Jesus as its Head and the Holy Spirit as its Soul. As Christ’s Church walks with God through time and space, it’s absolutely imperative to be a healthy cell within the mystical body as it ascends into heaven, joining its divine Head.