In speaking about the Trinity, the older theologians were fond of a Latin phrase derived from Augustine: opera ad extra Trinitatis sunt indivisa—“the external works of the Trinity are undivided.” Confusing? Not really. The idea is simply that the three persons of the Trinity are totally united, not only in what they are (God) but in what they do. The works of Father, Son, and Spirit in creation, providence, and redemption are marked by the deepest Trinitarian unity.
For example, it would be wrong to say that only God the Father created the universe, as if the Son and the Spirit were spectators, cheering Him on from the sidelines. Scripture makes it clear that all three persons shared fully in creating the universe. The Son is Creator as much as the Father: “All things were made through Him” (John 1:3). The Spirit is Creator as much as the Son: “ ‘The Spirit of God has made me’ ” (Job 33:4).
Neither is it the case that the Father created a third of the universe, the Son a third, and the Spirit the remaining third (as if the Father made the animals, the Son the vegetables, and the Spirit the minerals). No, each person of the Trinity created the whole universe: one single universe, one act of creation, proceeding simultaneously from Father, Son, and Holy Spirit in united omnipotent action.
I am not sure whether there is any very good analogy to this from the world of created things, unless perhaps it is the procreation of a child. The child is equally the offspring of its father and of its mother, and not of one more than the other. The two parents cooperate in the one action of producing the new life. In a faintly similar way, the three persons of the Trinity cooperated in the one action of producing the new entity, the cosmos. As the parents would say of the child, “Our child,” so the Trinity says of the universe, “Our creation.” There can be no exclusive “I” and “mine” here. The Father says, “I and My Son and My Spirit made the stars.” The Son says, “I and My Father and the Spirit fashioned the earth and sea.” The Spirit says, “I and the Father and the Son created man in Our image, according to Our likeness.”
The same mystery pertains to all the other works of the Trinity. It pertains, therefore, to the irresistible grace of the Trinity—that is, to the application of redemption. Let’s explore this.
God was in Christ reconciling the world to Himself. But how does that reconciliation actually touch the life of a person? How do we come to participate experientially in this reconciliation? We could say: “It is entirely up to us. The salvation is there. We now have to apply it to ourselves. We simply have to choose, to decide, to act.” But this would betray a mind-boggling lack of Biblical realism about human nature. If we are left to ourselves, we will ignore salvation and go on sinning, until we sin ourselves into hell. As Benjamin Warfield said, a gospel of “Whosoever will” is not much use in a world of universal “Won’t!”
Or we could say that the application of redemption is a joint work God prompts us, gives us a spiritual push (to overcome our lethargic depravity), and we then have to run in the direction He pushes us. And so, between God and ourselves, we enter into salvation. But this still leaves it ultimately up to us. Will we or will we not cooperate with God’s push? If we don’t, we frustrate Him. If we do, we have at best enabled God to save us (which doesn’t sound much like the Biblical idea of salvation or of God).
The true view is that God Himself sovereignly applies redemption to sinners. Everything that we do, however we may describe it—repenting, believing, converting, coming to Christ, receiving Christ, looking to Christ, calling upon the name of the Lord, turning from idols to the true and living God—it is all the outcome of God’s work in us. He moves us to do all these things. And He moves us sovereignly, omnipotently, efficaciously, leaving no room for our sin to thwart His gracious purpose. He slays our sin and graces us with willing hearts.
But what God is it that does these wondrous things? It is the triune God. And so everything we have said about the creation of nature we must say about the re-creation of grace. The almighty, efficacious grace that applies redemption to sinners is a Trinitarian grace. It flows from Father, Son, and Holy Spirit, one gushing Trinitarian fountain of salvation.