The Church Fathers say that the Catholic Church was formed on Good Friday.  Indeed, this is when the water flowing from the pierced Sacred Heart of Jesus was more than symbolic for the water that would one day wash us clean of sin in baptism.  Was not the Roman soldier, St. Longinus, washed clean by that very water as he pierced the Sacred Heart of Jesus with his own spear and believed in Him?  Furthermore, the Church Fathers teach that the Most Precious Blood that flowed from Christ’s pierced heart on the day of His crucifixion is literally the same as the blood that fills the priest’s chalice after the consecration at Holy Mass.  Hence, we are on firm ground to hold that the Catholic Church’s sacraments were formed on Holy Thursday (establishing the Eucharist and Holy Orders) as well as Good Friday (a continuation of the Holy Eucharist as Calvary and the Eucharist are one single sacraments.)

Some other people claim that the Catholic Church was founded at Pentecost.  Indeed, just before His Ascension, Christ tells His Apostles: It is not for you to know times or seasons that the Father has fixed by His own authority. But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem and in all Judea and Samaria, and to the end of the earth.—Acts 1:7-8.  This is a clear reference to why the Church will exist:  To bring glory to God by evangelizing the nations through miracles, healings, teachings and sacraments.

I compare Good Friday to the creation of Eve out of the side of Adam and then Pentecost to the time shortly after that when life was breathed into her.  The Church reflects Eve.  She is brought from the side of the New Adam (Christ) who was crucified.  Scripture says only of Adam (not Eve) this line about God breathing life into him: Then the Lord God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature.—Gen 2:7.  However, several verses later we read:  And the rib that the Lord God had taken from the man, He made into a woman and brought her to the man.—Gen 2:22.  If we can assume that God also breathed into Eve after creating her from Adam’s side (but before bringing her alive to Adam) then we have the analogy for Pentecost:  The Church is brought from the side of the New Adam opened on Good Friday, but life is breathed into her on Pentecost Sunday to bring new life to the world.

Perhaps we could say the Catholic Church was conceived on Good Friday and born on Pentecost.  On that first day of Pentecost, the Holy Spirit descended not so much upon Mary as through Mary (as Mediatrix of all graces) to the Apostles.  Mary is truly the New Eve, the exemplar of the nascent Church, freshly born of the bloody side of her spouse, the crucified Christ, now risen.  So, the Church is now fully alive, with Mary as her spotless center, with nearly infinite energy.  Now the Church—in the lives of the Apostles—is ready to forgive sins in baptism and confession on every continent, just as Christ gave them such power at His Resurrection: And when He had said this, He breathed on them and said to them, “Receive the Holy Spirit. If you forgive the sins of any, they are forgiven them; if you withhold forgiveness from any, it is withheld.”—John 20:22-23