Catholic homily outline for the Solemnity of the Most Holy Trinity – Year B

Central idea: God reveals who he is by what he does. Doctrine: The Blessed Trinity. Practical application: Devotion to the Blessed Trinity.

Written as an aid for homilists and a resource for the faithful, this doctrinal homily outline (1) provides insights into the Lectionary readings, (2) explicates a doctrine of Catholic Faith or morals from them, and (3) shows specific ways lay persons can live these truths. (To read more about this approach, click here.)

To view Lectionary 165, click here.

Central idea: God reveals who he is by what he does

Reading 1 Dt 4:32-34, 39-40

Moses said to the people:

“Ask now of the days of old, before your time,
ever since God created man upon the earth;
ask from one end of the sky to the other:
Did anything so great ever happen before?
Was it ever heard of?
Did a people ever hear the voice of God
speaking from the midst of fire, as you did, and live?
Or did any god venture to go and take a nation for himself
from the midst of another nation,
by testings, by signs and wonders, by war,
with strong hand and outstretched arm, and by great terrors,
all of which the LORD, your God,
did for you in Egypt before your very eyes?
This is why you must now know,
and fix in your heart, that the LORD is God
in the heavens above and on earth below,
and that there is no other.
You must keep his statutes and commandments that I enjoin on you today,
that you and your children after you may prosper,
and that you may have long life on the land
which the LORD, your God, is giving you forever.”

• In history, by his actions, the only almighty God has revealed himself to Israel and has done good to her. Continuing to receive this good requires her keeping his revealed Law.
• God reveals his inner life by his works (CCC 236). Through the events of the history of Israel, God reveals that he is one, almighty, and good.

Responsorial Psalm Ps 33:4-5, 6, 9, 18-19, 20, 22

R. Blessed the people the Lord has chosen to be his own.

Upright is the word of the LORD,
and all his works are trustworthy.
He loves justice and right;
of the kindness of the Lord the earth is full.

By the word of the LORD the heavens were made;
by the breath of his mouth all their host.
For he spoke, and it was made;
he commanded, and it stood forth.

See, the eyes of the LORD are upon those who fear him,
upon those who hope for his kindness,
To deliver them from death
and preserve them in spite of famine.

Our soul waits for the LORD,
who is our help and our shield.
May your kindness, O LORD, be upon us
who have put our hope in you.

• Blessed the people the Lord has chosen to be his own. Who are the people the Lord has chosen to be his own?
  • God chose the whole human race in Adam and Noah.
  • He chose the Jews in Abraham, Moses, and David.
  • In Christ, God chooses Christians.
  • God chooses everyone but some don’t know it and some don’t want it.
  • Those who don’t know it need our apostolate. Those who don’t want it need our good example.

Reading 2 Rom 8:14-17

Brothers and sisters:

For those who are led by the Spirit of God are sons of God.
For you did not receive a spirit of slavery to fall back into fear,
but you received a Spirit of adoption,
through whom we cry, “Abba, Father!”
The Spirit himself bears witness with our spirit
that we are children of God,
and if children, then heirs,
heirs of God and joint heirs with Christ,
if only we suffer with him
so that we may also be glorified with him.

• As Moses recounted, the Lord did good to Israel. What is the good God does for us?
  • He leads us by the Spirit of God, by the Holy Spirit.
  • He blesses us with life and saves and sanctifies us.
  • The pinnacle of what God does for us is that he adopts us to be children of God. This is why we can call God the Father, “Abba.”

Alleluia Rev 1:8

Glory to the Father, the Son, and the Holy Spirit;
to God who is, who was, and who is to come.

• We glorify God—who he is and what he does—by being his glorious handiwork.
• How then can we be glorious? We can do so through contemplation of truth, enjoyment of beauty, and especially doing good, even in suffering.
• In the Eucharist, we glorify God by our gifts, prayer, and praise. In the Eucharist, God glorifies us by giving us his Son and the Holy Spirit.

Gospel Mt 28:16-20

The eleven disciples went to Galilee,
to the mountain to which Jesus had ordered them.
When they all saw him, they worshiped, but they doubted.
Then Jesus approached and said to them,
“All power in heaven and on earth has been given to me.
Go, therefore, and make disciples of all nations,
baptizing them in the name of the Father,
and of the Son, and of the Holy Spirit,
teaching them to observe all that I have commanded you.
And behold, I am with you always, until the end of the age.”

• As we saw in the first reading, Moses declares the one God and orders Israel to keep the commandments Moses enjoins on them.
• Now, Christ declares the three persons in the one God and commissions his disciples to make disciples of all nations through baptism and keeping Christ’s commands.
• Just as Moses’ revelation was for the good of the Jews and their children in their earthly life, Christ’s revelation is for our good and the good of our children so that we may have eternal life.

Doctrine: The Blessed Trinity

• At the core of our Catholic faith is the mystery of the Trinity, and the invitation for us to participate in this divine life (Homiletic Directory §21).
• This reality about God is revealed and man’s salvation is effected through the Paschal Mystery (HD §21), which is re-presented in this Mass.
• What is revealed about God?
  • There is only one God. Yet within this one God there are three persons, the Father, the Son, and the Holy Spirit.
  • Jesus reveals that God “is Father not only in being Creator; he is eternally Father in relation to his only Son, who is eternally Son only in relation to his Father: ‘No one knows the Son except the Father, and no one knows the Father except the Son and any one to whom the Son chooses to reveal him’ (Mt 11:27)” (CCC 240).
  • This is why “the apostles confess Jesus to be the Word: ‘In the beginning was the Word, and the Word was with God, and the Word was God’; as ‘the image of the invisible God’; as the ‘radiance of the glory of God and the very stamp of his nature’ (Jn 1:1; Col 1:15; Heb 1:3)” (CCC 241).
  • This is why, “following this apostolic tradition” the Church calls the Son “consubstantial with the Father, that is, one only God with him” (CCC 242).
  • And, as we will affirm in the Creed, the Holy Spirit “proceeds from the Father and the Son.” To explain, “The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one principle and through one spiration…. And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son.” (CCC 246).
  • As the Athanasian Creed summarizes this: “The Father is made of none, neither created nor begotten. The Son is of the Father alone; not made nor created, but begotten. The Holy Spirit is of the Father and of the Son; neither made, nor created, nor begotten, but proceeding.”
• One very accessible image we have of the Blessed Trinity is the human family.
  • Like the Father, “In the procreation and education of children [the family] reflects the Father’s work of creation.
  • Like the Son, the family “is called to partake of the prayer and sacrifice of Christ. Daily prayer and the reading of the Word of God strengthen it in charity.
  • And like the Holy Spirit, “the Christian family has an evangelizing and missionary task.” (CCC 2205)“The Christian family is a communion of persons, a sign and image of the communion of the Father and the Son in the Holy Spirit.”

Practical application: Devotion to the Blessed Trinity

• This week we can make the Sign of the Cross and pray the Doxology with more awareness and gratitude for what the Blessed Trinity has done for us and with longing to see these divine persons face to face.
• We can also mediate on how our families—whether families of birth or of marriage—was, is, or could better an image of the Blessed Trinity.