The Time of the Promises
From the Catechism of the Catholic Church, Simplified
The Spirit's Words about Christ (702)
Until Christ's coming (the "fullness of time") the joint mission of the Son and the Spirit remained hidden. Both the Son and the Spirit were to be watched for. Therefore, the Church searches the Old Testament for what the Spirit, by inspiring the authors, tells us about Christ.
Creation - Both at Work (703-704)
God's Word and God's Breath are present at the origin of every creature. The Spirit "preserves creation in the Father through the Son" (Byzantine liturgy).
"God fashioned man with his two hands (the Son and the Spirit) so that even what was visible would bear the divine form" (St. Irenaeus).
The Promised Progeny (705-706)
God's promise to Abraham began the work of salvation which culminated in the Son, who assumed human nature, restored it to the Father's likeness, and gave it God's Glory, the Spirit.
God promised Abraham a progeny in which all the nations would be blessed. This progeny is Christ himself (Gal 3:16). God promised to give both his Son and Holy Spirit, "the guarantee of our inheritance" (Eph 1:13-14).
The Spirit Revealing Yet Concealing (707-708)
In the Old Testament manifestations, Christian Tradition saw that the Word allowed himself to be seen and heard, while the cloud of the Spirit both revealed God and concealed him.
God gave the Law as a teacher to lead people to Christ. Although man found the law powerless to save, his growing awareness of sin enkindled a desire for the Holy Spirit.
God Amidst Israel's Infidelity (709-710)
God's Law should have governed Israel. Unfortunately, Israel gave in to the temptation to become a kingdom like the other nations.
Because of their infidelity, Israel was led into the Exile (seemingly the failure of the promises). However, God began the restoration of his people and the purified remnant of exiles prefigured the Church.
The Spirit Prophesying the Messiah (711-713)
Two prophetic lines developed among this purified remnant. One led to an expectation of the Messiah and the other to the expectation of the Spirit.
In his "Book of Emmanuel," Isaiah prophesied that the Messiah would come from "the stump of Jesse," saying that "the Spirit of the Lord shall rest upon him" (Isa 11:1-2). Isaiah's Servant Song (C 42, 49 and 50) prophesied that the Messiah would "pour out the Holy Spirit."
The Spirit and Jesus (714-716)
Jesus quoted Isaiah in saying, "The Spirit of the Lord God is upon me because the Lord has anointed me" (61:1-2). Peter proclaimed that the prophecies about God sending the Spirit had been fulfilled at Pentecost. These prophecies describe a time when God's Spirit would renew men's hearts, reconcile peoples, and transform creation.
Before Jesus returns, the Spirit would bring about "a people prepared for the Lord" (Lk 1:17). These "people of the poor" would rely on God's plans and would not seek the justice of men, but of the Messiah.