Catechism in a Year
Sunday, May 06, 2018
143. What is the relationship between the Spirit and Christ Jesus in his earthly mission?
Beginning with his Incarnation, the Son of God was consecrated in his humanity as the Messiah by means of the anointing of the Spirit. He revealed the Spirit in his teaching, fulfilled the promises made to the Fathers, and bestowed him upon the Church at its birth when he breathed on the apostles after the Resurrection.
Further reading: CCC 727-730, 745-746
144. What happened at Pentecost?
Fifty days after the Resurrection at Pentecost the glorified Jesus Christ poured out the Spirit in abundance and revealed him as a divine Person so that the Holy Trinity was fully manifest. The mission of Christ and of the Spirit became the mission of the Church which is sent to proclaim and spread the mystery of the communion of the Holy Trinity.
"We have seen the true Light, we have received the heavenly Spirit, we have found the true faith: we adore the indivisible Trinity, who has saved us."
(Byzantine Liturgy, Troparion of Vespers of Pentecost)
Further reading: CCC 731-732, 738
These excerpts are from the Compendium of the CCC.