This is an extract from “Who is God?” available from our publications page. In Matthew 3, when Jesus gets baptised, we see the Father speaking and the Holy Spirit hovering over Jesus in the appearance of a dove. In other words The Trinity is present. So what does it mean for Christians to believe that God is Trinity?
Mike Reeves, opens his book “The Good God” with this comment:
“God is love”: those three words could hardly be more bouncy. They seem lively, lovely and as warming as a crackling fire. But ‘God is a Trinity’? No hardly the same effect, that sounds cold and stodgy.
But like me, Reeve’s is firmly convinced that the two phrases go hand in hand, adding, “Yes the Trinity can be presented as a fusty and irrelevant dogma, but the truth is that God is love because God is a Trinity.”
For the Bible tells me so
We find the phrase “God is Love” in a letter that the apostle John wrote. One of John’s concerns was to ensure that his readers would not be led astray by false teachers and in 1 John 4 he gives advice on how to discern whether or not something is from God or not. In verse two he tells us: “This is how you recognise the Spirit of God: Every Spirit that acknowledges that Jesus has come in the flesh is from God.”
In other words, if we want to know whether someone who claims to be speaking from and for God is telling the truth then a key test will be what they have to say about Jesus and his incarnation. Yarborough says that “This is often and plausibly taken as a rebuttal of the Docetism that arose in the early church and competed with the view that Jesus was both fully God and fully human.” You see, there were two errors doing the rounds about Jesus at the time John wrote. For some people, Jesus was just an ordinary man, maybe a very clever, wise, spiritual and loving man but just a man. Others believed that Jesus was very special, a spiritual being sent from God who appeared in human guise but wasn’t actually a real human being. He just had that appearance. John mainly has that second error in his sites here. Jesus really did “come in the flesh,” he was fully human. However to talk about Jesus coming is to use incarnational language –the idea that Jesus came to earth from heaven. Jesus did not start to exist at his birth. He himself claimed to have been in existence before his famous ancestor, Abraham.
John then goes on to say that the evidence of true faith is not just in what we say and believe but in what we do and how we live. Specifically, he says that we should “love one another because love comes from God.” Love marks us out and shows whether or not we really are from God because and it is at this point that he introduces us to that vital and wonderful phrase “God is love”
A Christian is someone who relates to God as Father (Jesus talks about our conversion as being like “new birth” – John 3:16) and so they should share something of his characteristic traits, just as a human child reflects his or her human father and mother’s characteristics including looks and personality. God is love, it is something essential to his character and so we should reflect it in our lives by loving one another.
Now this is the really important bit. John goes on to describe a little about what he means by the word love. Love means that God takes the initiative; he loves us before we love him. Love is demonstrated in a very specific event: God “sent his only Son into the World that we might live through him.” Ultimately this love is seen on the Cross; “he loved us and sent his Son as an atoning sacrifice for our sins.”
See here that ethics (how we should live) are explicitly tied into doctrine (what we should believe). See also that the idea that God is love is firmly rooted in Trinitarian Thinking. We cannot talk about God and love without talking about the Father and the Son. Why is this so?
How can God be love?
What I find really exciting about John’s little phrase, what makes those three words “bounce” is that John does not simply say “God loves.” It’s not just that God chooses at some point in history to start loving his creation. God is love. This is a quality or characteristic that is essential to him. It’s not something that he started to do and it’s not something that he will stop doing. It is in God’s nature to go on and on loving. I remember as a child in Sunday School singing a slightly quaint little chorus to the tune of Puff the Magic Dragon (I kid you not). It went something like this.
Love is like a circle, a circle big and round
For when you see a circle no ending can be found
And so the love of Jesus goes on eternally
Forever and forever, I know that God loves me
Now if we had just taken the first two lines on their own then we could not say them without any certainty of truth. Love does not always go on without ending. Relationships end, people hurt one another, death comes, love fades. There is no guarantee of “happy ever after”. However, the song isn’t simply an ode to the concept or feeling of love but specifically to God’s love and whoever wrote it insisted (correctly according to John) that this love is eternal.
It is only because God exists as a Trinity that he can be love. Why do we insist on this? Well let’s just think through what it would mean if God was not Trinity. This would mean that before God began to create, he was completely and utterly alone, a single person. Such a being could not really love because it had nothing and no-one to love unless it just loved itself (we call that narcissism).
Then at some point, this being chose to create the Universe and start to love its creatures. This would mean two things. First of all that God changed, he went from not loving to loving. Secondly it would make God dependent on his creation, he made the world because he needed something to love. It is fascinating that religions that deny the Trinity often want to emphasise that God is unchanging and that God is sovereign and yet they end up with a God who must change and who far from being sovereign is dependent. Such religions if followed consistently must require us to deny that God is Love.
Mike Reeve’s helpfully paints the picture of what this alternative God is like. We would know such a God primarily as Creator and Ruler. Reeve’s provides three propositions about our relationship to such a God.
First of all, if God’s very identity is to be the Creator, the Ruler, then he needs a creation to rule in order to be who he is. For all his cosmic power, then, God turns out to be pitifully weak: he needs us.
If God is the Ruler and the problem is that I’ve broken the rules, the only salvation he can offer is to forgive me and treat me as if I had kept the rules.
This means that He becomes a “traffic cop” God
And so thirdly:
If salvation simply means him letting me off, and counting me as a law abiding citizen then gratitude (not love) is all I have. In other words, I can never really love the God who is essentially just ‘The Ruler.’ And that ironically means I can never keep the greatest commandment: to love the Lord my God. 
John’s picture of God is far more wonderful. God is Love because he is eternally love. The Father eternally loves the Son lavishing his affection to him. The Son eternally loves the Father, delighting to please and obey him. The Spirit eternally loves the Father and the Son seeking to bring glory and honour to them. Therefore, God creates, not out of need but out of grace, creation is an outworking, an overflow of his love and his joy. God loves us first. God does not change. He did not start to love. His love is eternal. He will not stop being love. We can have confidence in his love and care.
This means that we can know God as Father and know that we are loved by him. It means that the right response is to love him back and so we can and should obey the first and greatest commandment to love God with all our heart, mind and strength.
 Michael Reeves, The Good God: Enjoying Father, Son and Spirit (Milton Keynes: Paternoster, 2012), vii.
 Reeves, The Good God, vii
 Yarborough, 1-3 John (ECNT), 223.
 1 John 1:7.
 1 John 4:7-8.
 1 John 4:10.
 1 John 4:9.
 1 John 4:10.
 Reeves, The Good God, 1.
 Reeves, The Good God, 2.
 Reeves, The Good God, 2.
 Reeves, The Good God, 2.