Divine blessedness is not a solitary perfection. It is the eternal, relational joy of Father, Son, and Holy Spirit and the fountain of every creaturely delight and the measure of all true happiness.

Scripture locates God’s blessedness inside the triune relations. The Son is “the radiance of the glory of God and the exact imprint of his nature” (Heb 1:3). The Word possesses “life in himself” (John 5:26), and that life is “the light of men” (John 1:4). Jesus prays that his disciples may behold the glory given him by the Father “before the foundation of the world” and share the love and joy that have always existed between Father and Son (John 17:24–26). Blessedness, therefore, is not an abstract attribute added to God. Blessedness is the living communion of the three.

Thomas Aquinas saw that the infinitely good God cannot be sterile. Infinite goodness must be fruitful, or it would be less than the finite goodness we see in creatures who beget their own kind. Scripture therefore speaks real relations into the Godhead: “You are my Son, today I have begotten you” (Ps 2:7; Heb 1:5). “From everlasting I was established … when there were no depths I was brought forth” (Prov 8:23–25). The Father begets the Son not in time but eternally; the Son is the perfect image in whom the Father delights without shadow or lack. This Fatherhood and Sonship is the very shape of divine blessedness. The Father contemplates his own infinite goodness and, in one act of perfect knowledge, speaks the Word who is “God of God, Light of Light.” The Father and Son together breathe forth the Spirit who is the mutual love and joy of both. The Trinity is not three gods agreeing to share; the Trinity is one God whose simple, blessed life is irreducibly relational, generative, and joyous. To confess “God is blessed” is to confess “God is Father, Son, and Holy Spirit.”

Divine glory is simply this blessedness made manifest. When Moses dares to ask, “Show me your glory,” God replies, “I will make all my goodness pass before you” (Exod 33:18–19). Isaiah’s seraphim do not cry “Power! Power! Power!” but “Holy, holy, holy” (Isa 6:3)—the moral beauty that radiates from perfect life. John sees the incarnate Word and declares, “We have seen his glory, glory as of the only Son from the Father, full of grace and truth” (John 1:14). Glory is not an aura added to God; it is the shining forth of the joy that Father, Son, and Spirit have in one another from all eternity.

The post-reformation scholastics (Mastricht, Turretin, Boston) rightly insist that God’s ultimate end in creation and redemption is the manifestation of this glory. Yet because glory is the effulgence of blessedness, the manifestation of God’s glory and the happiness of the creature are not competitors. God is most glorified in us when we are most satisfied in him. “Man’s chief end is to glorify God and enjoy him forever.” This is not a pious compromise; it is a theological necessity. Creatures reach their telos only by entering, through grace, the very joy that constitutes God’s triune life.

That entrance is the promise of the gospel. The Son became flesh so that we “may have fellowship with the Father and with his Son Jesus Christ” (1 John 1:3) and that our “joy may be full” (1 John 1:4). The Spirit is given as the down-payment of the inheritance until we “enter into the joy of our Master” (Matt 25:21, 23). The beatific vision is not cold contemplation; it is the soul’s final rest in the same delight that the Father has in the Son and the Son in the Father, perfected by the Spirit of love.

Therefore the doctrine of the Trinity is not an optional appendix to the doctrine of God; it is the only possible grammar for a God who is infinitely and eternally blessed. A unitarian deity might be powerful, but he would be lonely. A binitarian deity might converse, but it would lack the perfection of mutual love. Only the triune God—Father, Son, Spirit—possesses life in its absolute fullness. Only the triune God is blessed without shadow of lack or possibility of increase.

The gospel is nothing less than to Come and share the joy your heart was made for. This is the joy that has been enjoyed between Father, Son, and Spirit before the worlds began.