The conception of God in the Old Testament was important for understanding the development of the Christian Doctrine of the Trinity.
The early Christians, through the paschal mystery and the sending of the Spirit had experienced God as Father, Son and Holy Spirit and when they began their triadic reflections of God, they looked to the old testament for symbols, images and motifs to try to explain it. They reinterpreted the OT testament writings through the prism of Christ, looking for signs that this is what God had meant from the beginning.
Jesus referred to God as Father and in the OT, God was Father to all of Israel by virtue of His choosing them for Himself (not related to procreation). God was the ever faithful Father who loved, nurtured and protected Israel like a son or child because of the covenantal relationship based on bringing them out of Egypt. St Paul in Gal 4:4 explains that at the right time, the Father sent Jesus to save his people - the definitive intervention of God in history.
In the OT it was also common to refer to prophets and kings as sons of God and the messianic promise held that their savior would be a Davidic King, a true son of God. Jesus was shown to be that son with a unique sonship, a divine sonship.
Here the OT vivid personifications of Wisdom/Word and Spirit - mediators of God’s power were concepts and images that were closely identified with God and divine activity and yet distinct, helped talk about the God that is a Trinity. Texts about the Word of God, Lady Wisdom/Sophia and the Spirit provided some ways to separate but still hold together for one God.
Now, when St. Paul called Jesus the Wisdom of God and St John called Jesus the Logos or the Word, the NT writers attributed to Christ the characteristics of these personifications of God’s power from the OT. Wisdom was said to be eternal, with God from the beginning, active in creation and particularly related to human beings. Sophia (Wisdom) was said to save...