Where does the NT explain Tri-Unity?

The Announcement to Mary

Luke 1:32, 35—The Holy Spirit will come upon you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God. He will be great and will be called the Son of the Most High. The Lord God will give him the throne of his father David,

The Baptism of Christ

Matthew 3:16–17—The Son emerges from the water as the Father speaks and the Spirit descends as a dove.

Christ’s High-Priestly Prayer

            John 14:16–17—The Son asks the Father to send the Spirit (also 15:26).

The Baptismal Formula

Matthew 28:19—Baptize them in the name of the Father and of the Son, and of the Holy Spirit.

The Apostolic Benediction

2 Corinthians 13:14—May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all.

The NT Formula for Prayer

           Ephesians 2:18—Through [Christ] we have access to the Father by one Spirit.

The Trinitarian Nature of God’s Electing Work

           1 Peter 1:2—[You] have been chosen according to the foreknowledge of God the Father, through the sanctifying work of the Spirit, for obedience to Jesus Christ and sprinkling by his blood. See also 2 Thessalonians 2:13–14.

The Trinitarian Nature of God’s Atoning Work

           Hebrews 9:14—Christ through the eternal Spirit offered himself unblemished to God.

The Christian’s Trinitarian Confidence

            Jude 20–21—As you pray in the Holy Spirit, keep yourselves in God’s love as you wait for the mercy of our Lord Jesus Christ to bring you to eternal life.