Are the Divine Persons foreshadowed in the Old Testament?

CCC 772. From the beginning until “the fullness of time,” the joint mission of the Father’s Word and Spirit remains hidden, but it is at work. God’s Spirit prepares for the time of the Messiah. Neither is fully revealed but both are already promised, to be watched for and welcomed at their manifestation. So, for this reason, when the Church reads the Old Testament, she searches there for what the Spirit, “who has spoken through the prophets,” wants to tell us about Christ.

Like the Trinity Itself some allusions to the three Divine Persons can be found—the mystery being reserved for revelation in and through Jesus Christ.

Father The use of the title Father for God is found in some places. Moses, for example, chastising Israel, says,

Deuteronomy 32:6 Do you thus repay the LORD, you foolish and senseless people? Is not he your father, who created you, who made you and established you?

And the prophet Isaiah, praising God, addresses Him as father, saying,

Is. 64:8 Yet, O Lord, you are our father; we are the clay, and you are our potter; we are all the work of your hand.

However, such references were only understood to be saying something about God’s relationship with His chosen people.

Son The use of the title Son in the sense of the Divine Nature was also unknown. Used in conjunction “God” it was only with the sense of likeness to God in holiness. In the book of Job the angels are referred to as “sons of God” (Job 1:6, 2:1 & 38:7), and in Genesis 6:2 it is the righteous among men (cf. also Ps 29:1, 89:6; Wisdom 5:5).

Holy Spirit Similarly, throughout the Old Testament the Spirit of God is spoken of in equivocal terms—characteristic of God’s activity in creation and salvation history, yet not as a person. He moves over the creation, breathes life into man (Gen 1:3; 2:7), as well as renews him (Ps. 104:29-30). He gives power to the righteous (1 Sam. 10:9-13), and withdraws it from sinners (1 Sam 16:14). He speaks through the prophets, to chastise (Ezek. 2:2-3), and to promise renewal (Is. 11:2; 61:1).

Ezekiel 36:26-27 A new heart I will give you, and a new spirit I will put within you; and I will take out of your flesh the heart of stone and give you a heart of flesh. And I will put my spirit within you, and cause you to walk in my statutes and be careful to observe my ordinances.

Thus, while a common Hebrew word for “breath” or “wind” (ruah) is used, that God’s spirit has a personal activity attributed to it foreshadows the Divine Person revealed as such by Christ.