The Father and the son revealed by the spirit
The eternal origin of the Holy Spirit is revealed in his mission in time. The Spirit is sent to the apostles and to the Church both by the Father in the name of the Son, and by the Son in person, once he had returned to the Father. The sending of the person of the Spirit after Jesus' glorification reveals in its fullness the mystery of the Holy Trinity.
Source: Catechism of the Catholic Church (Vatican.va)