If someone were to tell us that knowing God is Three Persons in One is an easy concept to understand, we would have to declare them either a simpleton or a liar. But if someone were to tell us that this concept of the Trinity makes all the difference to how we interact with him in adoration and joy, with his overflowing love as the driving engine of our evangelism, we may just stop and ask this rejoicing Christian to explain. And Michael Reeves, president and professor of theology at Union School of Theology in the UK, does just that in Overflow: How the Joy of the Trinity Inspires Our Mission.

There is a reason that Christ commanded, “Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit” (Matt. 28:19, bold italics mine), and Reeves does a great job spelling it out for us simply and convincingly in this short book that will leave a lasting impact.

Charles Spurgeon once said this: “The most excellent study for expanding the soul, is the science of Christ, and him crucified, and the knowledge of the Godhead in the glorious Trinity. Nothing will so enlarge the intellect, nothing so magnify the whole soul of man, as a devout, earnest, continued investigation of the great subject of the Deity. And, whilst humbling and expanding, this subject is eminently consolatory. Oh, there is, in contemplating Christ, a balm for every wound; in musing on the Father, there is a quietus for every grief; and in the influence of the Holy Ghost, there is a balsam for every sore. Would you lose your sorrows? Would you drown your cares? Then go, plunge yourself in the Godhead’s deepest sea; be lost in his immensity; and you shall come forth as from a couch of rest, refreshed and invigorated. I know nothing which can so comfort the soul; so calm the swelling billows of grief and sorrow; so speak peace to the winds of trial, as a devout musing upon the subject of the Godhead.” (p. 11)

Reeves shows us that “the Trinity is not a weird puzzle for theological nerds but glorious good news for every Christian to enjoy”; that “the radiantly self-giving nature of God as the wellspring of all love, joy, goodness—and mission” is revealed from Genesis to Revelation; that when the Trinity is denied, love is denied; and “how, when Christians share God’s own outgoing fullness and radiance, we shine as lights in this current darkness.”

Reeves writes, “Mission is rooted in the Trinity, in the very being and nature and heart of God. And this is something deeply heart-winning and attractive in Him. If there is one thing I really want, above all, to communicate in this book, it is the great truth that God is mission. Wherever you’re at with God, particularly if you aren’t too thrilled with Him at the moment, I’d love for your eyes to be opened so you see just how stunningly beautiful and satisfying He is. I pray that your heart begins—maybe for the first time in a long time, maybe for the first time ever—to burn with a love for Him. Not just a duty that compels you and tells you what you ought to do, but rather, that you truly love Him! And then, out of this deep love, you will want to see the whole world come to know about Him too.” (p. 18)

“Mission is the outworking of God’s very nature. Before we ever did anything for Him, this God comes and gives His life away for us. So mission does not start with something we do, but with something done for us” (p. 48).

“Mission is the overflow of love from the enjoyment of divine fellowship. As we partake in the Father’s pleasure in His Son, and the Son’s pleasure in His Father, and the Spirit’s enlivening of their mutual love, it causes us to share their love for the world. Thus we become like what we worship. It is then, friend, you will want to sing of Him: when you are basking in the sunshine of God’s love. Because, as Jesus said, the ‘mouth speaks from the overflow of the heart’” (Luke 6:45 HCSB) (p. 56).

Reeves reminds us of the Father’s eternal love, what Christ has done for us on the Cross, and the Spirit’s regeneration, and encourages us to live in the light of this gospel truth: “You can live by the flesh, which means living under a spirit of slavery, always propelled by an insatiable lack, by guilt, by greed, by the desire to justify yourself. Or you can live as a child of God, by the Spirit of adoption.” (p. 82) “The children of God live from a fullness of life, a fullness of blessing. We can’t help but overflow with it. Other people need it too.” (p. 89)

This book is full of encouragement for those who feel themselves spiritually weary or empty. It is Christ-centered, Gospel-proclaiming, and Trinitarian-affirming and celebrating. I heartily recommend it.