While many answers might be tossed on the table to answer this question, not least the cross and resurrection, Brian Harris, in his book The Big Picture: Building Blocks of a Christian World View, offers an approach to worldview that includes a topic that seems rarely put on the table but which just might be the most significant Christian “addition” to worldview discussions. The Trinity. He knows what many will says:
When people hear that you are about to speak on the Trinity, their eyes usually glaze over, and you sense that an internal conversation is progressing along the lines of ‘Oh dear. Here we go again. Another exercise in improbable mathematics and unconvincing analogies. Does it actually matter? (131).
Three persons, one being. Three in One God, separable but equal in being. Brian clarifies an important point:
In every action of God all three persons work together as one. This means that if you want to know what the Father thinks, you can ask the Son; if you want to know what the Son thinks, you can ask the Father. There is no tension or competition in the activities of the three persons of the Trinity. The Trinity is a communion of persons. Never think of God in solitary terms. God is never lonely for God is the perfect community of love – a love that is deeply relational. ‘God is love’ finds its first expression in the relationship between the three persons of the Trinity (132).
This Trinity — this communion at the heart of Godness, this Three-in-One-ness — is what distinguishes Christianity from Islam (as Miroslav Volf made clear in his book Allah). Brian also points to problems (esp down the road as Trinity works out in life) in modalism, in tritheism and in subordinationalism — it turns God into a hierarchy with the Father being the most important and the Spirit a distant third.
Harris also sketches “Rahner’s rule”: the economic Trinity and the immanent Trinity, the God of history and the God as God is in himself. Rahner argued that the economic Trinity is the immanent Trinity and the immanent Trinity is the economic Trinity, which means God’s revelation in history is true to who God actually is. We learn of God through what God has revealed in history. The God of the revelation in the incarnate, crucified and raised Son then is the real God.
The best apologetic for the church is when the church really is the church and does what church is designed to do. This church is participation in the perichoretic dance of the Trinity. The church ought to be a display of Trinity.
This means first of all that individualism finds its place in community not in aloneness.
This means we will be a community of surprise (the Father’s surprising revelations). The Creator God is full of explosive surprises throughout the universe, in creation and in redemption. Interaction, relationship, alteration, shift, change.
This means we will be a community of embrace (the Son’s embrace of us in redemption). Here we encounter love, grace, forgiveness, reconciliation, and restoration — and this is to be seen in the Trinitarian church. But what is the church known for? Instead of God’s embrace we are known too often for God’s rejection or God’s headlock.
This means we will be a community of witness (the Spirit’s witness to the Father and Son). As the Spirit witnesses, so the church is a witness to Someone Else, not to itself. Bring back the Spirit and the church can be more of a witness.
For a brief moment forget every image that promptly springs into mind when you hear the word ‘church’. Imagine instead the rich Trinitarian life of the God revealed as Father, Son and Spirit. Ponder the way the Father is revealed though the pages of Scripture. Remember the embrace of the Son to a multitude of unlikely candidates. Recall the transformation of the disciples at Pentecost. If God will be who God has been, and if God will do what God has done, could it be that we can expect new versions of church to spring into being? Perhaps in the future we might participate in communities of surprise, embrace and witness. The nature of our triune God should prompt us to settle for nothing less. And if we were shaped by a God of surprise, embrace and witness, the emperor would no longer parade naked (147).