There are divine acts in which only one person is involved, acts that God performs within his own being (opera ad intra), such as the Father’s begetting of the Son.1John M. Frame, Systematic Theology: An Introduction to Christian Belief (Phillipsburg, NJ: P&R Publishing, 2013), 479–80. But all three persons perform all that God does in and for creation, the opera ad extra in the traditional terminology, the works of God that terminate outside himself.
Creation
Father
We know the Father was active in creation because of the repeated “And God said, let there be…” (Gen 1:1–2:3), and I won’t belabor that point here.
Son
Scriptures also show that the Son was active. We see it in the opening of John’s Gospel when he talks of the role of the Logos in creation: “God created everything through him, and nothing was created except through him” (John 1:3). Paul echoes and specifies: “through him God created everything in the heavenly realms and on earth. He made the things we can see and the things we can’t see—such as thrones, kingdoms, rulers, and authorities in the unseen world. Everything was created through him and for him” (Col 1:16).
Spirit

In the creation account itself, we read “The earth was formless and empty, and darkness covered the deep waters. And the רוּחַ/ruach of God was hovering over the surface of the waters” (Gen 1:2). So some go with the person of the “Spirit” (ASV, ESV, NASB), some leave it as “spirit,” an agency of the Godhead (Geneva, KJV, JPS, RSV, NRSV), which may also be rendered as “breath” (NLT, NJPS).
Job confesses, “the רוּחַ/ruach of God has made me, and the נְשָׁמָה/neshamah of the Almighty gives me life” (Job 33:4). We might insist that since the רוּחַ/ruach is the active agent, we must translate with “Spirit,” a direct reference to the third person of the Trinity (e.g., KJV, NLT, ESV, NASB, NET). But if we followed parallelism strictly, we would note that the נְשָׁמָה/neshamah “breath” is also an active agent; so we might end up claiming that the “breath” of God as a fourth person in the Godhead. So NJPS, RSV, NRSV).
The psalmist notes, “When you give them your רוּחַ/ruach, life is created, and you renew the face of the earth” (Ps 104:30). The Hebrew word ruach can be variously translated “Spirit,” “spirit,” “wind,” or “breath,” depending upon the context. We probably wouldn’t look at this as an Old Testament foretaste of regeneration, whereby the “Spirit” gives life. So translations tend to translate this as a reference to divine agency rather than a direct reference to the third person of the Trinity. In other words, we’ll see “your spirit” or even “your breath.”
But even if you see this as divine “breath,” you’re seeing it as the divine ruach bringing life. The same goes for the testimony of Job and the psalmist’s words.
Incarnation

“So the Word became human and made his home among us…. the Father’s one and only Son” (John 1:14). By defininition the Son is involved in the incarnnation. But we see distinct roles for each of the three members of the Trinity in the Annunciation. The angel told Mary, “The Holy Spirit will come upon you, and the power of the Most High (Father) will overshadow you. So the baby to be born will be holy, and he will be called the Son of God” (Luke 1:35).
Resurrection
Perhaps nowhere in the New Testament is the Godhead’s work so clearly shared by all three members of the Trinity than in Jesus’s own resurrection from the dead.
Paul opens Galatians ascribing it to the Father: “This letter is from Paul, an apostle. I was not appointed by any group of people or any human authority, but by Jesus Christ himself and by God the Father, who raised Jesus from the dead” (Gal 1:1). But it’s also reasonable for Jesus to tell his disciples, “I sacrifice my life so I may take it back again. No one can take my life from me. I sacrifice it voluntarily. For I have the authority to lay it down when I want to and also to take it up again” (John 10:17–18).
Paul also ascribes Jesus’s resurrection to God (i.e., the Father) and the Spirit: “The Spirit of God, who raised Jesus from the dead, lives in you. And just as God raised Christ Jesus from the dead, he will give life to your mortal bodies by this same Spirit living within you” (Rom 8:11).
Sanctification of Believers
As was the case with creation with Jesus’s incarnation and resurrection, our sanctification is the work of all three members of the Godhead: Father, the Son, and the Holy Spirit.
Paul pronounces a benediction over the Thessalonians that attributes the work to God the Father: “Now may the God of peace (Father) make you holy in every way, and may your whole spirit and soul and body be kept blameless until our Lord Jesus Christ comes again” (1 Thess 5:23).

The book of Hebrews declares that it’s the work of Jesus the Son: “Jesus suffered and died outside the city gates to make his people holy by means of his own blood” (Heb 13:12).
Peter lauds the work of election, sanctification, and growing in grace to the Trinity almost one-by-one: “God the Father knew you and chose you long ago, and his Spirit has made you holy. As a result, you have obeyed him and have been cleansed by the blood of Jesus Christ. May God (Father) give you more and more grace and peace” (1 Pet 1:2).
Paul has the same idea when he describes the Holy Spirit as the “Spirit of God” (i.e., the Father) and as “the Spirit of Christ” (i.e., the Son): “You are controlled by the Spirit if you have the Spirit of God living in you. (And remember that those who do not have the Spirit of Christ living in them do not belong to him at all)” (Rom 8:9).
Giving Gifts
Similarly, we see the Godhead fully involved with gifting the church. Exhorting the church to maintain unity, Paul used language sounding a lot like his description of the fruit of the Spirit in Galatians 5, then he rooted the church’s unity in Trinitarian faith:
Therefore I, a prisoner for serving the Lord, beg you to lead a life worthy of your calling, for you have been called by God. Always be humble and gentle. Be patient with each other, making allowance for each other’s faults because of your love. Make every effort to keep yourselves united in the Spirit, binding yourselves together with peace. For there is one body and one Spirit, just as you have been called to one glorious hope for the future. There is one Lord, one faith, one baptism, one God and Father of all, who is over all, in all, and living through all.
However, he has given each one of us a special gift through the generosity of Christ. That is why the Scriptures say,
“When he ascended to the heights,
he led a crowd of captives
and gave gifts to his people.” (Eph 4:1–8)
That last little bit about giving gifts is striking, in that Paul spends so much effort describing the gifts as from the Spirit, as gifts of the Spirit distributed as he will. And then here you read that they come “through the generosity of Christ,” the ascended Christ who “gave gifts to his people.” And that last little bit is Paul adapting language from a psalm that describes victorious “Lord God” (i.e., God the Father). I say “adapted,” because there the Father’s receiving gifts, like war tribute, rather than giving gifts: “When you ascended to the heights, you led a crowd of captives. You received gifts from the people, even from those who rebelled against you. Now the LORD God will live among us there” (Ps 68:18).
Such a great insight