Was it ever heard of?
Solemnity of the Most Holy Trinity
Deuteronomy 4:32-34, 39-40; Romans 8:14-17; Matthew 28:16-20
When we listen to today's words of Saint Paul, we can easily notice a reference to the Holy Trinity. The Apostle writes about the Spirit of God, the Father, and Jesus Christ. The Holy Spirit makes us the children of God and leads us to pray, "ABBA, Father!". As God's children, together with Christ, we are heirs of God. “Did anything so great ever happen before? Was it ever heard of?” (Deut. 4:32)
The mystery of the Holy Trinity is revealed in the election. The election of Israel from “the midst of another nation” (Deut. 4:34) foresees the calling of people to share in the life of God. The Church is a community of God's children chosen from all nations, peoples, and languages. God did great signs and wonders for Israel in Egypt. He has also made powerful signs for us in Jerusalem. The plagues broke Pharaoh's pride and gave freedom to Israel; the death and the resurrection of Christ defeated death and freed us from the tyranny of sin.
In the Old Testament, circumcision was a sign of the covenant, but the New Covenant is characterized by the sacrament of baptism. Christ commands the Church to baptize in the name of the Holy Trinity. Baptism brings us into communion with God. In this sacrament, we are united with Christ in his saving death and resurrection (see Rom. 6:3-4), we receive the gift of the Holy Spirit (see Titus 3:5), and are adopted as the children of God (Rom 8:15). The baptismal formula contains the words, "in the name (and not in the "names") of the Father and of the Son, and of the Holy Spirit", thus showing the unity of God as the Holy Trinity.
We owe to the Son the knowledge of God as the loving Father who cares for us (Matt. 11:27). The Son came into this world to accomplish the work that the Father gave to him (John 17:4), and when he completed the redemption of humanity, the Holy Spirit was sent upon us, so we can share in the unity which is between the Father and the Son (John 17:21-23). Thus the revelation of God as the Father, Son, and Holy Spirit is completed.
"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" (Deut 4:39). The experience of taking the people out of Egypt was intended to make both, Israel and the Egyptians, realize that the God of Abraham, Isaac, and Jacob is the Lord (Ex. 6:7, 7:5). This awareness obliges them to obey His commandments, that they may prosper and have a long life (Deut. 4:40). A similar call to obedience is also in today's Gospel. In addition to the baptism in the name of the Holy Trinity, as the full revelation of the One God, Jesus also commands: "Teach them (nations) to observe all that I have commanded you" (Matt. 28:19).
The mystery of the Holy Trinity permeates our entire Christian life. From the moment we were immersed in the water of baptism, we have entered into communion with each of the divine Persons. Since then, our life is marked by their actions. "Everyone who glorifies the Father does so through the Son in the Holy Spirit; everyone who follows Christ does so because the Father draws him and the Spirit moves him. "(CCC, 259). “Did anything so great ever happen before? Was it ever heard of?” (Deut. 4:32).