The first Sunday after Pentecost has been celebrated as a feast in honor of the Holy Trinity since the tenth century. Most festivals of the year celebrate a historical event, and although we celebrate a doctrine today, it is a doctrine based on historical events that revealed the nature of God as the Holy Trinity.
The first reading is from Proverbs. Here Wisdom speaks. She is the personification of God's mighty power. Wisdom describes herself as God's agent in creating the universe. Here we find an indication of the multipersonal God fully revealed as the Holy Trinity by Christ. In the reading from Romans, we find Paul articulating the growing discovery of the first Christians that we experience God's salvation as the work of the Father, of Jesus, and of the Holy Spirit.
In the Gospel reading from John, Jesus describes the work of the Father, the Spirit, and himself as the work of the one God. This is not a developed doctrine of the Trinity (one was not fully developed by the church until the fifth century), but in it God is described as a dynamic relationship into which we are incorporated through the Holy Spirit.
We come together to celebrate the Eucharist, and, called together by the Spirit, we encounter Christ in word and sacrament revealing the Father, and leading us into that eternal exchange of love which is at the heart of the Blessed Trinity.
Proverbs 8:1-4, 22-31
Does not wisdom call, and does not understanding raise her voice? On the heights, beside the way, at the crossroads she takes her stand; beside the gates in front of the town, at the entrance of the portals she cries out: "To you, O people, I call, and my cry is to all that live. The Lord created me at the beginning of his work, the first of his acts of long ago. Ages ago I was set up, at the first, before the beginning of the earth. When there were no depths I was brought forth, when there were no springs abounding with water. Before the mountains had been shaped, before the hills, I was brought forth - when he had not yet made earth and fields, or the world's first bits of soil. When he established the heavens, I was there, when he drew a circle on the face of the deep, when he made firm the skies above, when he established the fountains of the deep, when he assigned to the sea its limit, so that the waters might not transgress his command, when he marked out the foundations of the earth, then I was beside him, like a master worker; and I was daily his delight, rejoicing before him always, rejoicing in his inhabited world and delighting in the human race.
Domine, Dominus noster
1 O Lord our Governor,
how exalted is your Name in all the world!
2 Out of the mouths of infants and children
your majesty is praised above the heavens.
3 You have set up a stronghold against your adversaries,
to quell the enemy and the avenger.
4 When I consider your heavens, the work of your fingers,
the moon and the stars you have set in the courses.
5 What is man that you should be mindful of him?
the son of man that you should seek him out?
6 You have made him but little lower than the angels;
you adorn him with glory and honor;
7 You give him mastery over the works of your hands;
you put all things under his feet:
8 All sheep and oxen,
even the wild beasts of the field,
9 The birds of the air, the fish of the sea,
and whatsoever walks in the paths of the sea.
10 O Lord our Governor,
how exalted is your Name in all the world!
Since we are justified by faith, we have peace with God through our Lord Jesus Christ, through whom we have obtained access to this grace in which we stand; and we boast in our hope of sharing the glory of God. And not only that, but we also boast in our sufferings, knowing that suffering produces endurance, and endurance produces character, and character produces hope, and hope does not disappoint us, because God's love has been poured into our hearts through the Holy Spirit that has been given to us.
Jesus said to his disciples, "I still have many things to say to you, but you cannot bear them now. When the Spirit of truth comes, he will guide you into all the truth; for he will not speak on his own, but will speak whatever he hears, and he will declare to you the things that are to come. He will glorify me, because he will take what is mine and declare it to you. All that the Father has is mine. For this reason I said that he will take what is mine and declare it to you."