“God is love” (1 John 4:8).

From this simple, yet profound, statement about the nature of God, British theologian Michael Reeves draws a beautiful portrait of the biblical doctrine of the Trinity in Delighting in the Trinity, An Introduction to the Christian Faith (Downers Grove, IL: IVP, 2012). As the subtitle of the book suggests, a proper understanding of the Trinity shapes the entirety of Christian faith and practice. Reeves explores these ramifications regarding God’s identity as Father, Son and Spirit (chapter 1), creation (chapter 2), salvation (chapter 3), the Christian life (chapter 4), and the nature of God (chapter 5).

Why begin with the notion that “God is love”? Because “God could not be love if there was nobody to love” (p. 26). If love is truly essential to God’s nature, then God did not start loving after He created the world. He has always been a God of love. But if that is the case, who was God loving before there was a universe?

The biblical answer is the Son. “Father, I desire that they also, whom you have given me, may be with me where I am, to see my glory that you have given me because you loved me before the foundation of the world” (John 17:24). This in turn leads to a profound truth. If God is eternal, and if God’s very nature is love, then the Father must have loved the Son eternally. The Father has always been the Father, and the Son has always been the Son, and love has always existed between them. Reeves explains:

That is why it is important to note that the Son is the eternal Son. There was never a time when he didn’t exist. If there were, then God is a completely different sort of being. If there were once a time when the Son didn’t exist, then there was once a time when the Father was not yet a Father. And if that is the case, then once upon a time God was not loving since all by himself he would have had nobody to love (p. 27).

(Side note: this may seem like a very esoteric point, but its simplicity and beauty were brought home to me one Sunday morning in worship when one of our members, a truck driver – NOT a theologian – prayed, “Father, thank you for your Son, who is not like any other Son, but is a Son who is the same age as His Father.” That is spot on!)

Theologians call this doctrine the “eternal generation of the Son.” If God is eternally the Father, and the Son is eternally the Son, and yet the Son is begotten, that can only mean that the Son is somehow eternally generated or begotten. Reeves avoids this sort of theological jargon, and instead draws upon an ancient illustration to make the same point:

The Father is never without the Son but, like a lamp, it is the very nature of the Father to shine out his Son. And likewise, it is the very nature of the Son to be the one who shines out from his Father. In fact, he is the going out – the radiance – of the Father’s own being. He is the Son (p. 27).

And all of this reflects the truth that “God is love.”

But “the Father loves his Son in a very particular way,” Reeves goes on to argue, by pouring out his Holy Spirit (p. 29). Think of the scene at the baptism of Jesus. The Spirit descends from the Father onto the Son as the Father says, “This is my Son, whom I love” (Matthew 3:16-17). And so just as the Father begets the Son, the Father pours out the Spirit, and in the Spirit the Father and Son share eternal love.

And so we see that the Father, Son and Spirit, while distinct persons, are absolutely inseparable from each other. Not confused, but undividable. They are who they are together. They always are together, and thus they always work together (p. 34).

This is the classic doctrine of the Trinity.

But why is this a doctrine to delight in, as the title says? Because it means that since it is the very nature of the Father to overflow with love, His “outgoing nature” is to share this love with others through the Son and Spirit. This is why God created the world. As Reeves says, drawing from the work of Jonathan Edwards:

This God’s very self is found in giving, not taking. This God is like a fountain of goodness, and so, [Edwards] said, “seeking himself” means seeking “himself diffused and expressed” – in other words, seeking to have himself, his life and his goodness shared” (p. 47).

This also helps to explain what sin is – it is when human beings turn away from the outpouring of God’s love and into themselves. Sin is when our love is “misdirected and perverted” (p. 65) toward ourselves. But this does not change the nature of God. The eternal reality of the Son proceeding from the Father became an earthly reality when the Father sent the Son to take on human nature and atone for our sins.

Ultimately, the Father sent the Son because the Father so loved the Son – and wanted to share that love and fellowship. His love for the world is the overflow of his almighty love for his Son (p. 70).

This has enormous implications then for the Christian life.

“But if I am to be anything like the outgoing and out-ward looking Father, Son and Spirit, the Spirit must take my eyes off myself” (p. 93). And so we are called to share in this cascading love, love that stretches back into eternity and flows forth through us from God into the world.

This is a beautifully written book. And it is concisely written as well, every word of the 130 pages reflecting a craftsman at work. In addition to the fantastic content in the main text, Reeves also includes helpful sidebars with information about key historical figures in the development of this doctrine, as well as deeper theological reflections. Throughout the work Reeves also points out key differences between the Christian view of God and the Islamic view of God, which is extremely useful in light of the growth of Islam in the West.

I have just a few criticism of the work. Reeves comes from a Reformed perspective, so I would take issue with the few instances in which the doctrinal peculiarities of Calvinism shine through (such as his understanding of eternal security on p. 76). And at times it is not clear to me that Reeves properly applies passages about the incarnate Son when he discusses the eternal Son (such as his use of 1 Corinthians 11:3 on pp. 28 and 37). This lack of clarity may be on the receiving end, though!

If you would like a “starter” book on the Trinity, one that gets you excited about the meaning and significance of the doctrine, I can’t think of a better place to begin than Delighting in the Trinity.

(Many thanks to IVP for providing a free review copy!)